Dry sliding wear behaviour of ZE41A magnesium alloy (original) (raw)

Wear Mechanisms for Extruded AZ31B Magnesium Alloy during Dry Sliding Condition

In present work, the wear behaviour of extruded AZ31B magnesium alloy during dry sliding conditions has been investigated. The experiments were carried out using a pin-on-disc type wear apparatus against a steel disc counter face in an applied load range of 10-50 N, sliding velocity range of 0.1-0.9 m/sand at a constant sliding distance of 1000 m. The effect of applied load and sliding velocity on wear rate were analyzed. The wear surfaces were examined using a scanning electron microscope equipped with an energy dispersive spectrometer to reveal wear features. Wear mechanisms were analyzed at different sliding conditions. They were abrasion, oxidation, delamination, plastic deformation and melting.

Wear behaviour of AZ91D alloy at low sliding speeds

Wear, 2008

Effect of low sliding speeds (0.01-1.0 m s −1) on wear behaviour of an AZ91D magnesium alloy was studied under dry sliding condition using a pin-on-disc configuration. The wear rates were measured under a constant load of 10 N but two different sliding distances (1 and 10 km). Analyses of the wear tracks, worn surfaces and wear debris were carried out using scanning electron microscope and X-ray diffractometer. Thermogravimetric analyses were conducted to study oxidation behaviour of the wear debris. The friction coefficient values were found to fluctuate with increase in sliding speed leading to the three different wear transitions. Abrasive wear occurred during sliding at 0.01 m s −1. Oxidational wear was predominant at 0.1 m s −1 sliding speed. High sliding speed, 1.0 m s −1 , resulted in delamination wear. The wear rate was highest in abrasive wear and lowest in oxidational wear. Oxide particles of Mg-Al-O and MgO 2 were mainly observed in the abrasive wear. The majority of oxidational wear debris were oxides of Mg and Al in the form of MgO and MgAl 2 O 4. The largest amount of uncombined Mg was found in delamination wear debris.

Sliding wear behaviour of AZ31B magnesium alloy and nano-composite

Transactions of Nonferrous Metals Society of China, 2012

AZ31B magnesium alloy and nano-composite were manufactured by hybrid casting process and hot extruded at 350 C. The sliding wear behaviour of alloy and nano-composite was estimated at room temperature using the standard pin-on-disc wear test equipment. The tests were conducted under a normal load of 10 N at different sliding speeds ranging from 0.60 to 1.2 m/s for distance up to 2000 m. The wear mechanisms of the worn out surface were studied using SEM analysis. The influence of test parameters on wear rate of the pins was established using a linear regression model statistically. Compared with the AZ31B magnesium alloy, the nano-composite shows lower wear rates due to higher hardness improvement caused by the reinforcement. The wear mechanism appears to be a mix-up of ploughing, rows of furrows, delamination and oxidation.

Comparative study on wear behaviour of magnesium and aluminium alloys

Proceedings of the Institution of Mechanical Engineers, Part J: Journal of Engineering Tribology, 2006

Magnesium is the lightest metal used in structural applications, such as aerospace industry, and therefore, it provides the greatest potential for weight or energy reduction. It is particularly suitable for transport technology applications. In order to substitute aluminium alloys in aeronautical engines, wear behaviour of magnesium alloys is considered. A comparison of the unlubricated wear resistance of an aluminium alloy (A 357) and two magnesium alloys (AZ 91 and WE 43) rubbed against 52 100 bearing steel in a pin-on-ring configuration over a range of sliding speed (1-7 m/s) and applied normal loads (20-80 N) is established. In addition to the measurement of the friction force and wear depth, the temperature near the sliding contact is also measured using a thermocouple placed at the back of the pin sample. Thermal effect on friction and worn surfaces are observed and characterized. Wear transitions are found for the AZ 91 and the A 357 alloys. These transitions are controlled b...

Dry sliding wear behavior of globular AZ91 magnesium alloy and AZ91/SiCp composites

Wear, 2017

Dry sliding wear behavior of rheocast AZ91 magnesium alloy and AZ91/SiCp composites reinforced with 5 and 10 vol% SiC particles were investigated under normal loads of 10-250 N and sliding speeds of 0.1, 0.3, 0.5 and 1 m/s using pin-on-disc configuration against a 1045 steel disc counterbody. In this work, rheocast alloys and composites have been tested to determine the role played by the globular microstructure, and to evaluate if the increase observed in other mechanical properties is also translated to wear behavior. Wear rates and friction coefficients were registered during wear tests. Worn tracks and wear debris were studied by Scanning Electron Microscope (SEM) and Energy Dispersive X-Ray Spectrometry (EDS) in order to obtain the predominant wear mechanisms maps of the studied materials. The following wear mechanisms were found in the worn surface of the three materials: abrasion, oxidation delamination and melt wear. The composites with globular microstructure exhibit slightly superior wear resistance at low testing sliding speeds (0.1 and 0.3 m/s) and medium loads (40-80 N) than the AZ91 Mg alloy. But, for other conditions, the presence of SiC particles seems to be detrimental to the wear behavior of AZ91 magnesium alloy. A wear mechanisms map that allows identifying the main wear mechanisms for each wear condition and material composition has been developed. Rheocast microstructure improves the wear resistance of alloys in most conditions but the addition of SiCp reinforcement is only favorable in few of them.

2000-sliding-wear-map-for-the-magnesium-a

Dry sliding wear tests were performed on a Mg-9.0%, Al-0.9%, Zn (AZ91) alloy using a block on-ring (AISI 52100 steel) configuration. Wear rates were measured within a load range of 1-350 N and a sliding velocity range of 0.1-2.0 m/s Compositions, morphologies and microstructures of worn surfaces and wear debris were characterised by scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS) and X-ray diffractometer (XRD). A wear mapping approach, consisting of identification of micromechanisms of wear leading to the generation of loose debris and surface damage and determination of the range of applicability of each mechanism as a function of load and speed, has been adopted. Two main wear regimes, namely a mild wear regime and a severe wear regime have been observed. The role of contact surface temperature on the mild to severe wear transition was investigated in detail. It was shown that the transition from mild to severe wear was controlled by the contact surface temperature of the alloy and that the onset of the severe wear coincided with a surface temperature of 347 K. In the mild wear regime two different micromechanisms operated, i.e. two sub-wear regimes, namely an oxidational wear regime and a delamination wear regime, were identified. Similarly, in the severe wear regime two different wear mechanisms were responsible for surface damage and debris formation. These were classified as the severe plastic deformation induced wear and the melt wear regimes. The results of wear tests and metallographic investigations on worn surfaces have been summarised in a wear mechanism map. An empirical contact surface temperature model, which serves to predict the critical surface temperature at the onset of severe wear, has been developed.

Dry Sliding Wear Characteristics of Gravity Die-Cast Magnesium Alloys

The paper deals with the wear behavior of conventional cast Mg-Sn-based alloys. The alloys were studied through pin-on-disk wear test under four different loading conditions; namely, 9.8, 19.6, 29.4, and 39.2 N. The study highlights the cumulative wear loss, volumetric wear loss, dry sliding wear rate, and coefficient of friction of the alloys. The volumetric wear increased with increasing applied load. The wear mechanism was studied with scanning electron microscope. The wear occurs mainly by plowing mechanism and also by delamination. During wear, extensive plastic deformation and work hardening occurred. Microstructural analysis has been carried out for all the alloys at different loading conditions.

Effect of mechanical vibrations on the wear behavior of AZ91 Mg alloy

2018

AZ91 Mg alloy is the most promising alloy used for structural applications. The vibration induced methods are effective and economic viable in term of mechanical properties. Sliding wear tests were performed on AZ91 Mg alloy using a pin-on-disc configuration. Wear rates were measured at 5 N and 10N at a sliding velocity of 1m/s for varied frequency within the range of 5-25Hz and a constant amplitude of 2mm. Microstructures of worn surfaces and wear debris were characterized by field emission scanning electron microscopy (FESEM). It is observed that wear resistance of vibrated AZ91 alloy at 15Hz frequency ad 2mm amplitude was superior than cast AZ91 Mg alloy. Finer grain size and equiaxed grain shape both are important parameters for better wear resistance in vibrated AZ91 Mg alloys. FESEM analysis revealed that wear is considerably affected due to frictional heat generated by the relative motion between AZ91 Mg alloy and EN31 steel surface. No single mechanism was responsible for material loss.

Microstructural evolution of die-cast and homogenized AZ91 Mg-alloys during dry sliding condition

Journal of Magnesium and Alloys, 2017

Microstructural evolution of die-cast and homogenized AZ91 Mg-alloys was investigated during dry sliding wear condition. Tribological tests were performed using a pin-on-disc (EN8 steel) configuration with a normal load of 50 N at a constant sliding speed of 2.5 ms −1 under ambient environment. Delamination was recognized as a predominant wear mechanism in both of these materials. The die-cast AZ91 Mg-alloy exhibits lower coefficient of friction and higher wear rate. This can be ascribed to increase in the intensity of load bearing capacity of hard β-Mg17Al12 phase, and crack formation/de-cohesion at the interface between primary α-Mg and discontinuous β-Mg17Al12 phases. On the contrary, the homogenized AZ91 Mg-alloy experiences higher coefficient of friction and lower wear rate. The friction-induced microstructural evolution (supersaturated α-Mg to eutectic (α + β-Mg17Al12)) tending to minimize the wear rate by providing barrier to material removal in the near surface region of homogenized AZ91 Mg-alloy. Therefore, experimental observation revealed that an inverse relationship exists between wear rate and coefficient of friction for the investigated materials. The analysis of worn surfaces and subsurfaces by electron microscopy provided evidence to delamination wear and microstructural evolution.

Dry sliding wear of an AZ31 magnesium alloy processed by equal-channel angular pressing

Journal of Materials Science, 2013

A magnesium AZ31 alloy was processed by equal-channel angular pressing (ECAP) for up to 8 passes to reduce the grain size to *1.0 lm. Following ECAP, microhardness measurements were taken to evaluate the mechanical properties of the material. Ball-on-disc dry sliding tests were conducted to compare the wear behaviour of the as-received alloy and the alloy processed by ECAP. The surface topography and volume loss were recorded for all samples. The results show that the fluctuations and average values of the coefficient of friction are improved after processing by ECAP. In addition, there is a decrease in the wear depth and volume loss with increasing numbers of ECAP passes. The ECAP-processed alloy has a higher wear resistance than the unprocessed alloy and it is a suitable candidate material for use in industrial applications.