Dr. Bharat Padekar | Savitribai Phule Pune University (original) (raw)

Papers by Dr. Bharat Padekar

Research paper thumbnail of Corrosion Behaviour of Friction Stir Welded and Hard Anodized 7004 Aluminium Alloy

All the rights belong to the author(s). The material presented and the views expressed are solely... more All the rights belong to the author(s). The material presented and the views expressed are solely those of the author(s). NIGIS does not own the copyright of any information presented in this paper and is not responsible for any action arising out of this publication.

Research paper thumbnail of Paper No. CII15 CORROSION BEHAVIOUR OF ANNEALED AND HEAT TREATED -AGED 6061 ALUMINIUM ALLOY

Corrosion behaviour of annealed along with heat treated and aged 6061 aluminium alloy were studie... more Corrosion behaviour of annealed along with heat treated and aged 6061 aluminium alloy were studied in 3.5 wt. % NaCl solution using Potentiostat. Tafel plots were obtained to evaluate the corrosion rate. The corrosion potential of annealed specimen found to be-744.8 mV and corrosion current density as 1.489 µA/cm 2 and that to for heat treated-aged specimen corrosion potential observed to be-699 mV which is slightly nobler and slightly higher corrosion current density like 1.98 µA. This change in behaviour is attributed to change in morphology of grain boundary precipitate that are responsible for pitting like corrosion.

Research paper thumbnail of Stress Corrosion Cracking of a New Rare- Earth Containing Magnesium Alloy, Elektron21 Compared with AZ91E

Materials Science Forum, 2011

Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elek... more Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elektron21 was studied using constant load test (CLT) in 0.1N NaCl solution saturated with Mg(OH)2.For comparison a common Al-containing and RE-free alloy, AZ91E was investigated. In CLT the threshold stress for SCC (σscc) for AZ91E was found to be 60% of the yield stress, whereas Elektron21 showed immunity to SCC even at stresses in the proximity of yield stress. The susceptibility of AZ91E to SCC and immunity of Elektron21 during CLT have been confirmed by fractography.

Research paper thumbnail of Stress corrosion cracking behavior of magnesium alloys EV31A and AZ91E

Materials Science and Engineering: A, 2013

ABSTRACT The stress corrosion cracking of the sand cast magnesium alloys, Elektron 21 (ASTM-EV31A... more ABSTRACT The stress corrosion cracking of the sand cast magnesium alloys, Elektron 21 (ASTM-EV31A) and AZ91E, was studied using compact tension specimens in distilled water and in Mg(OH)(2) saturated 0.1 M NaCl solution under constant load. EV31A showed a higher K-ISCC than AZ91E, but exhibited a higher stage II crack growth rate than the latter. Fractography showed transgranular cracking for AZ91E and EV31A in distilled water, whereas mixed intergranular and transgranular cracking was observed for EV31A in the chloride environment. The crack propagation involved hydrogen embrittlement. (c) 2013 Elsevier B.V. All rights reserved.

Research paper thumbnail of Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80

Materials Science and Engineering: A, 2008

St r e s s cor r os i on cr acki ng (SCC) of t he hi gh-pe r f or mance r ar e-e ar t h cont ai n... more St r e s s cor r os i on cr acki ng (SCC) of t he hi gh-pe r f or mance r ar e-e ar t h cont ai ni ng mag ne s i um al l oys ZE41, QE22 and El e kt r on 21 (EV31A) was s t udi ed us i ng s l ow s t r ai n r at e t es t s (SSRT) i n ai r , di s t i l l ed wat e r and 0. 5 wt. % NaCl s ol ut i on. For compar i s on, t he wel l known AZ80 al l oy was al s o s t udi e d. Al l t he f our al l oys (AZ80, ZE41, QE22 and EV31A) we r e s us ce pt i bl e t o SCC i n 0. 5wt. % NaCl s ol ut i on and di s t i l l e d wat e r. AZ80 had s i mi l ar SCC s us ce pt i bi l i t y i n di s t i l l e d wat e r and 0. 5 wt. % NaCl s ol ut i on. ZE41, QE22 and EV31A had hi ghe r s us ce pt i bi l i t y t o SCC i n 0. 5 wt .

Research paper thumbnail of Role of chlorides on pitting and hydrogen embrittlement of Mg–Mn wrought alloy

Corrosion Science, 2013

Resumo: O objetivo do artigo é discutir o conceito de movimentos sociais, propondo a discussão a ... more Resumo: O objetivo do artigo é discutir o conceito de movimentos sociais, propondo a discussão a partir da ideia de tradição (Stuart Hall). Essa noção advém do debate existente entre as teorias de mudança social e as concepções de emancipação, no âmbito do pensamento pós-marxista. Também apresentamos alguns elementos do debate teórico acerca dos movimentos sociais no Brasil. Esses elementos serviram de base para propormos que os agentes dos movimentos sociais criaram, historicamente, uma tradição de revolucionários (no sentido usado por Hall). A inscrição de suas lutas atua como uma memória discursiva que atua como impulso para sua práxis política. A partir dessa tradição surgem os diversos grupos que tentam encarnar a promessa de revolução e emancipação humana (proposta por Marx).

Research paper thumbnail of Determination of threshold stress intensity factor for stress corrosion cracking (KISCC) of steel heat affected zone

Research paper thumbnail of Stress corrosion cracking of a wrought Mg–Mn alloy under plane strain and plane stress conditions

Engineering Fracture Mechanics, 2013

Research paper thumbnail of Stress corrosion cracking behavior of EV31A and Mg-Mn magnesium alloys

Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attrac... more Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attractive for light weight applications, such as automotive and aerospace industries. The primary motive of alloy development has been to impart high strength and creep resistance. However, all Mg-alloys are vulnerable to various forms of corrosion including stress corrosion cracking (SCC) due to high thermodynamic driving force. So research relating to various form of corrosion including SCC is important. In this work mechanism(s) of SCC of a sand cast alloy EV31A (Mg-0.28Zn-0.6Zr-2.9Nd-1.5Gd-0.14 other rare earth (RE) (each <0.01%)-<0.001Ag-<0.0001Cu-0.003Fe-<0.0001Ni) and a wrought alloy Mg-Mn hot rolled (Mg-0.1Al-0.3Zn-1.75Mn-0.25Ce-0.3(other rare earths)) was also studied. AZ91E, a well known alloy was studied as a reference. Several complementary techniques were employed. Optical micrography and X-ray diffraction (XRD) were used for phase analysis. Slow strain rate test (SSR...

Research paper thumbnail of Hot Salt Stress Corrosion Cracking Study of Selective Laser Melted Ti-6Al-4V Alloy

Journal of Materials Engineering and Performance, 2021

The hot salt stress corrosion cracking (HSSCC) behavior of the selectively laser melted (SLM) Ti-... more The hot salt stress corrosion cracking (HSSCC) behavior of the selectively laser melted (SLM) Ti-6Al-4V alloy in the as-built and heat-treated conditions was studied at 300 and 400 °C. The HSSCC resistance of very susceptible as-built alloy can be significantly increased through annealing at 750 °C, losing only a small amount of ultimate tensile strength (UTS). The improvement in the HSSCC resistance is brought out by a transformation of martensite into lamellar α + β. The absence of equiaxed α found in the wrought alloy seems to help in increasing the HSSCC resistance of SLM Ti-6Al-4V alloy at high strength level.

Research paper thumbnail of Stress corrosion cracking of a recent rare-earth containing magnesium alloy, EV31A, and a common Al-containing alloy, AZ91E

Corrosion Science, 2013

ABSTRACT Stress corrosion cracking of the magnesium alloy Elektron 21 (ASTM–EV31A) and AZ91E was ... more ABSTRACT Stress corrosion cracking of the magnesium alloy Elektron 21 (ASTM–EV31A) and AZ91E was studied using constant load test in 0.1 M NaCl solution (saturated with Mg(OH)2), and slow strain rate test using glycerol, distilled water and Mg(OH)2 saturated, 0.01 M and 0.1 M NaCl solutions. Slow strain rate test indicated that EV31A was less susceptible to stress corrosion cracking than AZ91E. Under less intense loading of constant load, EV31A was found to be resistant to stress corrosion cracking. Fractography of EV31A specimens showed little evidence of hydrogen embrittlement. The superior resistance of EV31A is attributed to a more robust oxide/hydroxide layer.

Research paper thumbnail of Stress Corrosion Cracking Behavior of EV31A and Mg-Mn Magnesium Alloys

Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attrac... more Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attractive for light weight applications, such as automotive and aerospace industries. The primary motive of alloy development has been to impart high strength and creep resistance. However, all Mg-alloys are vulnerable to various forms of corrosion including stress corrosion cracking (SCC) due to high thermodynamic driving force. So research relating to various form of corrosion including SCC is important. In this work mechanism(s) of SCC of a sand cast alloy EV31A (Mg-0.28Zn-0.6Zr-2.9Nd-1.5Gd-0.14 other rare earth (RE) (each <0.01%)-<0.001Ag-<0.0001Cu-0.003Fe-<0.0001Ni) and a wrought alloy Mg-Mn hot rolled (Mg-0.1Al-0.3Zn-1.75Mn-0.25Ce-0.3(other rare earths)) was also studied. AZ91E, a well known alloy was studied as a reference. Several complementary techniques were employed. Optical micrography and X-ray diffraction (XRD) were used for phase analysis. Slow strain rate test (SSR...

Research paper thumbnail of Stress corrosion cracking of a wrought Mg–Mn alloy under plane strain and plane stress conditions

Stress corrosion crack growth of a rare earth containing Mg–Mn hot rolled alloy was studied using... more Stress corrosion crack growth of a rare earth containing Mg–Mn hot rolled alloy was studied
using compact tension and circumferential notch tensile specimens employing constant
load in 0.1 N NaCl solution saturated with Mg(OH)2. Circumferential notch tensile
specimens satisfied plane strain conditions; Log crack velocity versus stress intensity plots
yielded slope of 0.5 and 1 for stage I region and threshold stress intensity of 10 and
13 MPa m1/2 for circumferential notch tensile and compact tension specimens respectively.
Fractography showed trans-granular features involving hydrogen in stress corrosion
cracking

Research paper thumbnail of Stress corrosion cracking behavior of magnesium alloys EV31A and AZ91E

The stress corrosion cracking of the sand cast magnesium alloys,Elektron21(ASTM-EV31A) and AZ91E,... more The stress corrosion cracking of the sand cast magnesium alloys,Elektron21(ASTM-EV31A) and AZ91E,
was studied using compact tension specimens in distilled water and in Mg(OH)2 saturated 0.1M NaCl
solution under constant load.EV31A showed a higher KISCC than AZ91E, but exhibited a higher stage II
crack growth rate than the latter.Fractography showed trans-granular crackingforAZ91EandEV31Ain
distilled water,whereasmixedintergranularandtransgranularcrackingwasobservedforEV31Ainthe
chloride environment.The crack propagation involved hydrogen embrittlement.

Research paper thumbnail of Stress Corrosion Cracking of Rare- Earth Containing Magnesium Alloy EV31A Compared With AZ91E Using Slow Strain Rate Test

Stress corrosion cracking (SCC) of the high performance rare-earth (RE) containing magnesium allo... more Stress corrosion cracking (SCC) of the high performance rare-earth (RE) containing magnesium alloy
Elektron 21 (ASTM - EV31A) was studied using slow strain rate test (SSRT). Glycerol, distilled water,
and 0.01 N and 0.1 N NaCl solutions saturated with Mg(OH)2 were employed. For comparison a wellknown
AZ91E alloy was also studied. SSRT studies indicate that both the alloys were susceptible to
SCC to some extent in 0.1 N, 0.01 N NaCl solutions and distilled water. However, EV31A showed
higher SCC resistance than AZ91E. The fractography of SSRT tested AZ91E and EV31A specimens
were largely found to be transgranular (TGSCC) in distilled water. However in 0.1 N and 0.01 N NaCl
solutions AZ91E exhibited transgranular, while EV31A showed mixed TGSCC and intergranular
(IGSCC) fracture involving hydrogen embrittlement. EV31A showed lower susceptibility to SCC in all
the three solutions than AZ91E, that is there is not much loss in mechanical properties of EV31A as
compared to that of AZ91E in these environments.

Research paper thumbnail of Stress corrosion cracking of a new rare- earth containing magnesium alloy, Elektron21 compared with AZ91E

Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elek... more Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium
alloy, Elektron21 was studied using constant load test (CLT) in 0.1N NaCl solution saturated with
Mg(OH)2. For comparison a common Al-containing and RE-free alloy, AZ91E was investigated. In
CLT the threshold stress for SCC (σscc) for AZ91E was found to be 60% of the yield stress, whereas
Elektron21 showed immunity to SCC even at stresses in the proximity of yield stress. The
susceptibility of AZ91E to SCC and immunity of Elektron21 during CLT have been confirmed by
fractography.

Research paper thumbnail of Determination of threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy using compact tension specimen

Threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy was d... more Threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy was determined using compact tension (CT) specimens of ½ T dimensions proportions having side groove of 5%T on each side. The specimens were tested under constant load condition and corrosive drip of 0.1 N NaCl solution saturated with Mg(OH)2. The stress corrosion crack velocity (vc) and the threshold stress intensity factor (KQSCC) were respectively determined to be 2.49X 10-10 m s-1 and 13.1 MPa m1/2. The paper discusses the mechanism of stress corrosion cracking (SCC) of the alloy. Fractography suggested transgranular SCC.

Research paper thumbnail of USE OF FORMING SIMULATION IN PREDECTING SPRING BACK, BLANK HOLDING FORCE AND THINNING EFFECT FOR HSS OR UHSS SHEET USED FOR WEIGHT REDUCTION OF BODY IN WHITE.

The objective of the present work is to investigate the possibilities of Weight reduction of Body... more The objective of the present work is to investigate the possibilities of Weight reduction of Body in White (BIW) using
Advanced or Ultra high strength steel sheet in the passenger car as against existing BIW consisting of mostly mild steel parts.
Using modern advanced high strength steels it is possible to produce safe, fuel-efficient, environmentally appropriate and
affordable vehicles. The automotive industry now uses a large proportion of mild steels with yield strengths of around 200
N/mm2. By changing over to extra and ultra high strength steels with yield strengths of up to 1150 N/mm2, great potential is
available for improving economy, performance and safety. High strength steels generally demand no new investments in
production equipment, as it can be processed using the existing equipment. It is hard to form the HSS/ UHSS using same press
and die set up but with the help of FEA forming simulation cost and time of whole process can be reduced, and problems of
formability can be answer. The necessary changes can be made in the shape of the component to over come some of the
forming issues such as spring back and wrinkles.
In a current work thinning effect, spring back effect and required blank holder force is compared using PAM STAMP 2G forming
simulation FEA software for same die surface and different sheet metal of reduced thickness with increased tensile strength

Research paper thumbnail of Slow Strain Rate Test and Constant Load Test on a Wrought Mg-Mn Alloy In 3.5 Wt. % Nacl Solution

Stress corrosion cracking of a rare earth containing wrought Mg-Mn alloy was studied using cylind... more Stress corrosion cracking of a rare earth containing wrought Mg-Mn alloy was studied using cylindrical tensile specimen in transverse and longitudinal axis alignment in 3.5 wt. % NaCl solution saturated with Mg(OH)2 using slow strain rate test. Specimens in transverse alignment were tested under constant load condition in the same solution. Mg-Mn alloy was found equally susceptible in both the axis alignment. The test data plot of stress against time to fail shows threshold stress of 42% yield stress. Fractography shows transgranular features involving hydrogen in stress corrosion cracking.

Research paper thumbnail of Stress Corrosion Cracking Studies of a Wrought Mg-Mn Alloy in Chloride Solutions Using Constant Load Technique

Stress corrosion cracking of a rare earth containing Mg-Mn hot rolled alloy was studied using cyl... more Stress corrosion cracking of a rare earth containing Mg-Mn hot rolled alloy was studied using cylindrical tensile specimen in long transverse alignment using constant load technique in 0.1 M and 0.6 M (3.5 wt.%) NaCl solutions saturated with Mg(OH)2. The test data plots of stress against time to fail show threshold stress of 126 MPa (90% σYS) and 60 MPa (42% σYS) in 0.1 M and 0.6 M NaCl test solutions respectively. The role of chloride has been found to be to damage the passive film, cause pitting and increasing hydrogen embrittlement tendency of the alloy. Fractography shows transgranular (TGSCC) features involving hydrogen in SCC. The second phase particles seem to assist the crack growth, as they are aligned along the rolling direction.

Research paper thumbnail of Corrosion Behaviour of Friction Stir Welded and Hard Anodized 7004 Aluminium Alloy

All the rights belong to the author(s). The material presented and the views expressed are solely... more All the rights belong to the author(s). The material presented and the views expressed are solely those of the author(s). NIGIS does not own the copyright of any information presented in this paper and is not responsible for any action arising out of this publication.

Research paper thumbnail of Paper No. CII15 CORROSION BEHAVIOUR OF ANNEALED AND HEAT TREATED -AGED 6061 ALUMINIUM ALLOY

Corrosion behaviour of annealed along with heat treated and aged 6061 aluminium alloy were studie... more Corrosion behaviour of annealed along with heat treated and aged 6061 aluminium alloy were studied in 3.5 wt. % NaCl solution using Potentiostat. Tafel plots were obtained to evaluate the corrosion rate. The corrosion potential of annealed specimen found to be-744.8 mV and corrosion current density as 1.489 µA/cm 2 and that to for heat treated-aged specimen corrosion potential observed to be-699 mV which is slightly nobler and slightly higher corrosion current density like 1.98 µA. This change in behaviour is attributed to change in morphology of grain boundary precipitate that are responsible for pitting like corrosion.

Research paper thumbnail of Stress Corrosion Cracking of a New Rare- Earth Containing Magnesium Alloy, Elektron21 Compared with AZ91E

Materials Science Forum, 2011

Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elek... more Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elektron21 was studied using constant load test (CLT) in 0.1N NaCl solution saturated with Mg(OH)2.For comparison a common Al-containing and RE-free alloy, AZ91E was investigated. In CLT the threshold stress for SCC (σscc) for AZ91E was found to be 60% of the yield stress, whereas Elektron21 showed immunity to SCC even at stresses in the proximity of yield stress. The susceptibility of AZ91E to SCC and immunity of Elektron21 during CLT have been confirmed by fractography.

Research paper thumbnail of Stress corrosion cracking behavior of magnesium alloys EV31A and AZ91E

Materials Science and Engineering: A, 2013

ABSTRACT The stress corrosion cracking of the sand cast magnesium alloys, Elektron 21 (ASTM-EV31A... more ABSTRACT The stress corrosion cracking of the sand cast magnesium alloys, Elektron 21 (ASTM-EV31A) and AZ91E, was studied using compact tension specimens in distilled water and in Mg(OH)(2) saturated 0.1 M NaCl solution under constant load. EV31A showed a higher K-ISCC than AZ91E, but exhibited a higher stage II crack growth rate than the latter. Fractography showed transgranular cracking for AZ91E and EV31A in distilled water, whereas mixed intergranular and transgranular cracking was observed for EV31A in the chloride environment. The crack propagation involved hydrogen embrittlement. (c) 2013 Elsevier B.V. All rights reserved.

Research paper thumbnail of Stress corrosion cracking of rare-earth containing magnesium alloys ZE41, QE22 and Elektron 21 (EV31A) compared with AZ80

Materials Science and Engineering: A, 2008

St r e s s cor r os i on cr acki ng (SCC) of t he hi gh-pe r f or mance r ar e-e ar t h cont ai n... more St r e s s cor r os i on cr acki ng (SCC) of t he hi gh-pe r f or mance r ar e-e ar t h cont ai ni ng mag ne s i um al l oys ZE41, QE22 and El e kt r on 21 (EV31A) was s t udi ed us i ng s l ow s t r ai n r at e t es t s (SSRT) i n ai r , di s t i l l ed wat e r and 0. 5 wt. % NaCl s ol ut i on. For compar i s on, t he wel l known AZ80 al l oy was al s o s t udi e d. Al l t he f our al l oys (AZ80, ZE41, QE22 and EV31A) we r e s us ce pt i bl e t o SCC i n 0. 5wt. % NaCl s ol ut i on and di s t i l l e d wat e r. AZ80 had s i mi l ar SCC s us ce pt i bi l i t y i n di s t i l l e d wat e r and 0. 5 wt. % NaCl s ol ut i on. ZE41, QE22 and EV31A had hi ghe r s us ce pt i bi l i t y t o SCC i n 0. 5 wt .

Research paper thumbnail of Role of chlorides on pitting and hydrogen embrittlement of Mg–Mn wrought alloy

Corrosion Science, 2013

Resumo: O objetivo do artigo é discutir o conceito de movimentos sociais, propondo a discussão a ... more Resumo: O objetivo do artigo é discutir o conceito de movimentos sociais, propondo a discussão a partir da ideia de tradição (Stuart Hall). Essa noção advém do debate existente entre as teorias de mudança social e as concepções de emancipação, no âmbito do pensamento pós-marxista. Também apresentamos alguns elementos do debate teórico acerca dos movimentos sociais no Brasil. Esses elementos serviram de base para propormos que os agentes dos movimentos sociais criaram, historicamente, uma tradição de revolucionários (no sentido usado por Hall). A inscrição de suas lutas atua como uma memória discursiva que atua como impulso para sua práxis política. A partir dessa tradição surgem os diversos grupos que tentam encarnar a promessa de revolução e emancipação humana (proposta por Marx).

Research paper thumbnail of Determination of threshold stress intensity factor for stress corrosion cracking (KISCC) of steel heat affected zone

Research paper thumbnail of Stress corrosion cracking of a wrought Mg–Mn alloy under plane strain and plane stress conditions

Engineering Fracture Mechanics, 2013

Research paper thumbnail of Stress corrosion cracking behavior of EV31A and Mg-Mn magnesium alloys

Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attrac... more Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attractive for light weight applications, such as automotive and aerospace industries. The primary motive of alloy development has been to impart high strength and creep resistance. However, all Mg-alloys are vulnerable to various forms of corrosion including stress corrosion cracking (SCC) due to high thermodynamic driving force. So research relating to various form of corrosion including SCC is important. In this work mechanism(s) of SCC of a sand cast alloy EV31A (Mg-0.28Zn-0.6Zr-2.9Nd-1.5Gd-0.14 other rare earth (RE) (each <0.01%)-<0.001Ag-<0.0001Cu-0.003Fe-<0.0001Ni) and a wrought alloy Mg-Mn hot rolled (Mg-0.1Al-0.3Zn-1.75Mn-0.25Ce-0.3(other rare earths)) was also studied. AZ91E, a well known alloy was studied as a reference. Several complementary techniques were employed. Optical micrography and X-ray diffraction (XRD) were used for phase analysis. Slow strain rate test (SSR...

Research paper thumbnail of Hot Salt Stress Corrosion Cracking Study of Selective Laser Melted Ti-6Al-4V Alloy

Journal of Materials Engineering and Performance, 2021

The hot salt stress corrosion cracking (HSSCC) behavior of the selectively laser melted (SLM) Ti-... more The hot salt stress corrosion cracking (HSSCC) behavior of the selectively laser melted (SLM) Ti-6Al-4V alloy in the as-built and heat-treated conditions was studied at 300 and 400 °C. The HSSCC resistance of very susceptible as-built alloy can be significantly increased through annealing at 750 °C, losing only a small amount of ultimate tensile strength (UTS). The improvement in the HSSCC resistance is brought out by a transformation of martensite into lamellar α + β. The absence of equiaxed α found in the wrought alloy seems to help in increasing the HSSCC resistance of SLM Ti-6Al-4V alloy at high strength level.

Research paper thumbnail of Stress corrosion cracking of a recent rare-earth containing magnesium alloy, EV31A, and a common Al-containing alloy, AZ91E

Corrosion Science, 2013

ABSTRACT Stress corrosion cracking of the magnesium alloy Elektron 21 (ASTM–EV31A) and AZ91E was ... more ABSTRACT Stress corrosion cracking of the magnesium alloy Elektron 21 (ASTM–EV31A) and AZ91E was studied using constant load test in 0.1 M NaCl solution (saturated with Mg(OH)2), and slow strain rate test using glycerol, distilled water and Mg(OH)2 saturated, 0.01 M and 0.1 M NaCl solutions. Slow strain rate test indicated that EV31A was less susceptible to stress corrosion cracking than AZ91E. Under less intense loading of constant load, EV31A was found to be resistant to stress corrosion cracking. Fractography of EV31A specimens showed little evidence of hydrogen embrittlement. The superior resistance of EV31A is attributed to a more robust oxide/hydroxide layer.

Research paper thumbnail of Stress Corrosion Cracking Behavior of EV31A and Mg-Mn Magnesium Alloys

Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attrac... more Magnesium alloys are the lightest metallic engineering materials, and hence they are quite attractive for light weight applications, such as automotive and aerospace industries. The primary motive of alloy development has been to impart high strength and creep resistance. However, all Mg-alloys are vulnerable to various forms of corrosion including stress corrosion cracking (SCC) due to high thermodynamic driving force. So research relating to various form of corrosion including SCC is important. In this work mechanism(s) of SCC of a sand cast alloy EV31A (Mg-0.28Zn-0.6Zr-2.9Nd-1.5Gd-0.14 other rare earth (RE) (each <0.01%)-<0.001Ag-<0.0001Cu-0.003Fe-<0.0001Ni) and a wrought alloy Mg-Mn hot rolled (Mg-0.1Al-0.3Zn-1.75Mn-0.25Ce-0.3(other rare earths)) was also studied. AZ91E, a well known alloy was studied as a reference. Several complementary techniques were employed. Optical micrography and X-ray diffraction (XRD) were used for phase analysis. Slow strain rate test (SSR...

Research paper thumbnail of Stress corrosion cracking of a wrought Mg–Mn alloy under plane strain and plane stress conditions

Stress corrosion crack growth of a rare earth containing Mg–Mn hot rolled alloy was studied using... more Stress corrosion crack growth of a rare earth containing Mg–Mn hot rolled alloy was studied
using compact tension and circumferential notch tensile specimens employing constant
load in 0.1 N NaCl solution saturated with Mg(OH)2. Circumferential notch tensile
specimens satisfied plane strain conditions; Log crack velocity versus stress intensity plots
yielded slope of 0.5 and 1 for stage I region and threshold stress intensity of 10 and
13 MPa m1/2 for circumferential notch tensile and compact tension specimens respectively.
Fractography showed trans-granular features involving hydrogen in stress corrosion
cracking

Research paper thumbnail of Stress corrosion cracking behavior of magnesium alloys EV31A and AZ91E

The stress corrosion cracking of the sand cast magnesium alloys,Elektron21(ASTM-EV31A) and AZ91E,... more The stress corrosion cracking of the sand cast magnesium alloys,Elektron21(ASTM-EV31A) and AZ91E,
was studied using compact tension specimens in distilled water and in Mg(OH)2 saturated 0.1M NaCl
solution under constant load.EV31A showed a higher KISCC than AZ91E, but exhibited a higher stage II
crack growth rate than the latter.Fractography showed trans-granular crackingforAZ91EandEV31Ain
distilled water,whereasmixedintergranularandtransgranularcrackingwasobservedforEV31Ainthe
chloride environment.The crack propagation involved hydrogen embrittlement.

Research paper thumbnail of Stress Corrosion Cracking of Rare- Earth Containing Magnesium Alloy EV31A Compared With AZ91E Using Slow Strain Rate Test

Stress corrosion cracking (SCC) of the high performance rare-earth (RE) containing magnesium allo... more Stress corrosion cracking (SCC) of the high performance rare-earth (RE) containing magnesium alloy
Elektron 21 (ASTM - EV31A) was studied using slow strain rate test (SSRT). Glycerol, distilled water,
and 0.01 N and 0.1 N NaCl solutions saturated with Mg(OH)2 were employed. For comparison a wellknown
AZ91E alloy was also studied. SSRT studies indicate that both the alloys were susceptible to
SCC to some extent in 0.1 N, 0.01 N NaCl solutions and distilled water. However, EV31A showed
higher SCC resistance than AZ91E. The fractography of SSRT tested AZ91E and EV31A specimens
were largely found to be transgranular (TGSCC) in distilled water. However in 0.1 N and 0.01 N NaCl
solutions AZ91E exhibited transgranular, while EV31A showed mixed TGSCC and intergranular
(IGSCC) fracture involving hydrogen embrittlement. EV31A showed lower susceptibility to SCC in all
the three solutions than AZ91E, that is there is not much loss in mechanical properties of EV31A as
compared to that of AZ91E in these environments.

Research paper thumbnail of Stress corrosion cracking of a new rare- earth containing magnesium alloy, Elektron21 compared with AZ91E

Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium alloy, Elek... more Stress corrosion cracking (SCC) of a rare-earth (RE) containing and Al-free magnesium
alloy, Elektron21 was studied using constant load test (CLT) in 0.1N NaCl solution saturated with
Mg(OH)2. For comparison a common Al-containing and RE-free alloy, AZ91E was investigated. In
CLT the threshold stress for SCC (σscc) for AZ91E was found to be 60% of the yield stress, whereas
Elektron21 showed immunity to SCC even at stresses in the proximity of yield stress. The
susceptibility of AZ91E to SCC and immunity of Elektron21 during CLT have been confirmed by
fractography.

Research paper thumbnail of Determination of threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy using compact tension specimen

Threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy was d... more Threshold stress intensity factor (KQSCC) of a rare earth containing Mg-Mn hot rolled alloy was determined using compact tension (CT) specimens of ½ T dimensions proportions having side groove of 5%T on each side. The specimens were tested under constant load condition and corrosive drip of 0.1 N NaCl solution saturated with Mg(OH)2. The stress corrosion crack velocity (vc) and the threshold stress intensity factor (KQSCC) were respectively determined to be 2.49X 10-10 m s-1 and 13.1 MPa m1/2. The paper discusses the mechanism of stress corrosion cracking (SCC) of the alloy. Fractography suggested transgranular SCC.

Research paper thumbnail of USE OF FORMING SIMULATION IN PREDECTING SPRING BACK, BLANK HOLDING FORCE AND THINNING EFFECT FOR HSS OR UHSS SHEET USED FOR WEIGHT REDUCTION OF BODY IN WHITE.

The objective of the present work is to investigate the possibilities of Weight reduction of Body... more The objective of the present work is to investigate the possibilities of Weight reduction of Body in White (BIW) using
Advanced or Ultra high strength steel sheet in the passenger car as against existing BIW consisting of mostly mild steel parts.
Using modern advanced high strength steels it is possible to produce safe, fuel-efficient, environmentally appropriate and
affordable vehicles. The automotive industry now uses a large proportion of mild steels with yield strengths of around 200
N/mm2. By changing over to extra and ultra high strength steels with yield strengths of up to 1150 N/mm2, great potential is
available for improving economy, performance and safety. High strength steels generally demand no new investments in
production equipment, as it can be processed using the existing equipment. It is hard to form the HSS/ UHSS using same press
and die set up but with the help of FEA forming simulation cost and time of whole process can be reduced, and problems of
formability can be answer. The necessary changes can be made in the shape of the component to over come some of the
forming issues such as spring back and wrinkles.
In a current work thinning effect, spring back effect and required blank holder force is compared using PAM STAMP 2G forming
simulation FEA software for same die surface and different sheet metal of reduced thickness with increased tensile strength

Research paper thumbnail of Slow Strain Rate Test and Constant Load Test on a Wrought Mg-Mn Alloy In 3.5 Wt. % Nacl Solution

Stress corrosion cracking of a rare earth containing wrought Mg-Mn alloy was studied using cylind... more Stress corrosion cracking of a rare earth containing wrought Mg-Mn alloy was studied using cylindrical tensile specimen in transverse and longitudinal axis alignment in 3.5 wt. % NaCl solution saturated with Mg(OH)2 using slow strain rate test. Specimens in transverse alignment were tested under constant load condition in the same solution. Mg-Mn alloy was found equally susceptible in both the axis alignment. The test data plot of stress against time to fail shows threshold stress of 42% yield stress. Fractography shows transgranular features involving hydrogen in stress corrosion cracking.

Research paper thumbnail of Stress Corrosion Cracking Studies of a Wrought Mg-Mn Alloy in Chloride Solutions Using Constant Load Technique

Stress corrosion cracking of a rare earth containing Mg-Mn hot rolled alloy was studied using cyl... more Stress corrosion cracking of a rare earth containing Mg-Mn hot rolled alloy was studied using cylindrical tensile specimen in long transverse alignment using constant load technique in 0.1 M and 0.6 M (3.5 wt.%) NaCl solutions saturated with Mg(OH)2. The test data plots of stress against time to fail show threshold stress of 126 MPa (90% σYS) and 60 MPa (42% σYS) in 0.1 M and 0.6 M NaCl test solutions respectively. The role of chloride has been found to be to damage the passive film, cause pitting and increasing hydrogen embrittlement tendency of the alloy. Fractography shows transgranular (TGSCC) features involving hydrogen in SCC. The second phase particles seem to assist the crack growth, as they are aligned along the rolling direction.