James Earthman | University of California, Irvine (original) (raw)

Papers by James Earthman

Research paper thumbnail of High temperature intergranular crack growth processes in copper and copper with 1 wt% antimony

Acta Metallurgica, 1985

ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K u... more ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K under various loading conditions. The presence of Sb in Cu facilitates brittle intergranular fracture at low temperatures and permits a study of cavitation at the crack tip using SEM techniques. Steep gradients in cavitation damage are observed under constant load conditions wherein the crack accelerates in the course of growth. With a constant stress intensity factor, the crack decelerates during growth and the cavitation spreads evenly over the ligament ahead of the crack tip. The crack growth rate is compared with the stress intensity factor and C*, which have been determined for different loading conditions. Results similar to those of Landes and Begley were obtained, indicating that C*, evaluated experimentally, correlates with crack growth rate under constant displacement rate conditions. Crack growth under constant displacement rate conditions can be described by a simple steady state model.

Research paper thumbnail of An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study

The Journal of Prosthetic Dentistry

Research paper thumbnail of Production and Characterization of Aluminium NbAl<sub>3</sub> Composite by Mechanical Alloying and In Situ - A Process Comparison

Trans Tech Publications Ltd. eBooks, Nov 15, 2005

Research paper thumbnail of Laser scanning crack detection for fine wire fatigue testing

Although fine wire is used in a variety of important applications, from massive woven ropes which... more Although fine wire is used in a variety of important applications, from massive woven ropes which support bridges to microcircuit connecting leads, the equipment and techniques for determining a wire product`s lifetime are not well developed. This can be largely attributed to the practical difficulties associated with testing sub-millimeter sized specimens. Since large specimens are not appropriate for evaluating the fatigue properties of fine wires, there is a need for a crack detection and monitoring technique that can be directly applied to the wires themselves. This presentation provides a description of a novel scanning laser crack detection technique that has been developed to detect fatigue cracking in specimens made directly from fine wire.

Research paper thumbnail of Fatigue Crack Growth Behavior of a Continuous Alumina Fiber Reinforced Metal Matrix Composite Materials

Journal of The Korean Society of Civil Engineers, Mar 1, 1991

Research paper thumbnail of Fatigue Crack Prognostics by Optical Quantification of Defect Frequency

Metallurgical and Materials Transactions, Nov 10, 2017

Research paper thumbnail of Introduction to Creep and Stress-Relaxation Testing

Research paper thumbnail of Lithium fluoride material properties as applied on the NIRCam instrument

Proceedings of SPIE, Aug 18, 2005

Research paper thumbnail of High temperature intergranular crack growth processes in copper and copper with 1 wt% antimony

Acta Metallurgica, May 1, 1985

ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K u... more ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K under various loading conditions. The presence of Sb in Cu facilitates brittle intergranular fracture at low temperatures and permits a study of cavitation at the crack tip using SEM techniques. Steep gradients in cavitation damage are observed under constant load conditions wherein the crack accelerates in the course of growth. With a constant stress intensity factor, the crack decelerates during growth and the cavitation spreads evenly over the ligament ahead of the crack tip. The crack growth rate is compared with the stress intensity factor and C*, which have been determined for different loading conditions. Results similar to those of Landes and Begley were obtained, indicating that C*, evaluated experimentally, correlates with crack growth rate under constant displacement rate conditions. Crack growth under constant displacement rate conditions can be described by a simple steady state model.

Research paper thumbnail of An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study

Journal of Prosthetic Dentistry, May 1, 2023

Research paper thumbnail of Quantitative percussion diagnostics for evaluating porosity and surface roughness of cold sprayed and laser deposited materials

Journal of materials research and technology, Sep 1, 2021

Abstract Quantitative percussion diagnostics (QPD) is a non-destructive evaluation method that ha... more Abstract Quantitative percussion diagnostics (QPD) is a non-destructive evaluation method that has been used successfully in a number of applications. This technique involves a rod that is actuated to impact a specimen with a given amount of kinetic energy and the resulting mechanical response of the specimen as a function of time is measured using a piezoelectric force sensor. The mechanical energy returned to the rod is then analyzed. Because contact with the specimen is on the order of a few hundred microseconds, QPD can be used in situations and for specimen conditions (e.g. high temperature) that are not feasible for other nondestructive testing methods. The objective of the present study was to evaluate the use of QPD for characterization of defects in specimens fabricated using two additive manufacturing methods, i.e. cold spray deposition and laser powder directed energy deposition (LPDED). Cold spray specimens were produced using commercially pure nickel with varied process conditions including gas type (i.e. helium and nitrogen) and deposition rate. In addition, a Ti–6Al–4V specimen was manufactured using LPDED with varying porosity content. All specimens were characterized using both QPD and destructive methods (i.e. cross-sectional metallography) to compare results for observed defect characteristics. Cold spray specimens exhibited a lower energy return when they contained more porosity and/or surface roughness. Microscopic plastic deformation at highly porous surfaces was indicated during percussion testing that reached a saturation level after repeated percussion. Overall, the results showed that QPD can effectively evaluate cold spray and LPDED specimens for porosity and surface roughness.

Research paper thumbnail of The Effect of Heat Treatment on the Corrosion Resistance of 440C Stainless Steel in 20% HNO<SUB>3</SUB> + 2.5% Na<SUB>2</SUB>Cr<SUB>2</SUB>O<SUB>7</SUB> Solution

Journal of Materials Engineering and Performance, Apr 1, 2003

The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated... more The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated in a 20% HNO3 + 2.5% Na2Cr2O7 solution using electrochemical noise (ECN) measurements, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) examinations. The noise resistance (Rn), which has been found to be inversely related to the localized corrosion rate, was measured to be 5.7E

Research paper thumbnail of Interaction of Calcium Carbonate with Nanobubbles Produced in an Alternating Magnetic Field

ACS Applied Materials & Interfaces, Aug 31, 2020

Research paper thumbnail of Creep and fracture of engineering materials and structures : proceedings of the Seventh International Conference held at the University of California, Irvine, August 10-15, 1997

Minerals, Metals & Materials Society eBooks, 1997

Research paper thumbnail of The Effect of Electrical Discharge Machining on Electro-Deposited Nano-Crystalline Ni Sheet

Microscopy and Microanalysis, Aug 1, 2007

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Fl... more Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Research paper thumbnail of Characterization of Low-cycle Fatigue Damage in Inconel 718 by Laser Light Scanning

Journal of Materials Research, Aug 1, 1997

Research paper thumbnail of Change of structure, creep fatigue behaviour and life of X 20 CrMoV 12 1

Research paper thumbnail of Reduction of calcified plaque volume in ex vivo pericardial tissue, with nanobubbles

Colloids and Surfaces B: Biointerfaces

Research paper thumbnail of Scanning Laser Detection of Crack Precursors in High RAP Content Asphalt Mixture with Improved Fatigue Performance

Formation of microcracks under fatigue conditions is a complex mechanism and difficult to detect.... more Formation of microcracks under fatigue conditions is a complex mechanism and difficult to detect. A microcrack is not apparent until late in fatigue life of the section. However, structural changes and microcracks can occur earlier and could be used as an originator for fatigue crack formations that lead to failure. Therefore, it is important to develop methods to promptly detect microcracks early in fatigue life well in advance of macrocrack growth. This paper presents the test procedure and analysis approach developed for a non-contact Scanning Laser Detection (SLD) for capturing and monitoring cracks in asphalt mixtures. The study focuses on utilizing SLD to investigate damage resistance of asphalt mixtures containing high Recycled Asphalt Pavement (RAP) content. Use of more RAP in asphalt materials is becoming increasingly popular due to the economic and environmental benefits of recycled materials. On the other hand, stiffer mixes resulting from RAP addition has raised concern ...

Research paper thumbnail of NANO HIGHLIGHT Ideal Strength and Nanomechanics

Research paper thumbnail of High temperature intergranular crack growth processes in copper and copper with 1 wt% antimony

Acta Metallurgica, 1985

ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K u... more ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K under various loading conditions. The presence of Sb in Cu facilitates brittle intergranular fracture at low temperatures and permits a study of cavitation at the crack tip using SEM techniques. Steep gradients in cavitation damage are observed under constant load conditions wherein the crack accelerates in the course of growth. With a constant stress intensity factor, the crack decelerates during growth and the cavitation spreads evenly over the ligament ahead of the crack tip. The crack growth rate is compared with the stress intensity factor and C*, which have been determined for different loading conditions. Results similar to those of Landes and Begley were obtained, indicating that C*, evaluated experimentally, correlates with crack growth rate under constant displacement rate conditions. Crack growth under constant displacement rate conditions can be described by a simple steady state model.

Research paper thumbnail of An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study

The Journal of Prosthetic Dentistry

Research paper thumbnail of Production and Characterization of Aluminium NbAl<sub>3</sub> Composite by Mechanical Alloying and In Situ - A Process Comparison

Trans Tech Publications Ltd. eBooks, Nov 15, 2005

Research paper thumbnail of Laser scanning crack detection for fine wire fatigue testing

Although fine wire is used in a variety of important applications, from massive woven ropes which... more Although fine wire is used in a variety of important applications, from massive woven ropes which support bridges to microcircuit connecting leads, the equipment and techniques for determining a wire product`s lifetime are not well developed. This can be largely attributed to the practical difficulties associated with testing sub-millimeter sized specimens. Since large specimens are not appropriate for evaluating the fatigue properties of fine wires, there is a need for a crack detection and monitoring technique that can be directly applied to the wires themselves. This presentation provides a description of a novel scanning laser crack detection technique that has been developed to detect fatigue cracking in specimens made directly from fine wire.

Research paper thumbnail of Fatigue Crack Growth Behavior of a Continuous Alumina Fiber Reinforced Metal Matrix Composite Materials

Journal of The Korean Society of Civil Engineers, Mar 1, 1991

Research paper thumbnail of Fatigue Crack Prognostics by Optical Quantification of Defect Frequency

Metallurgical and Materials Transactions, Nov 10, 2017

Research paper thumbnail of Introduction to Creep and Stress-Relaxation Testing

Research paper thumbnail of Lithium fluoride material properties as applied on the NIRCam instrument

Proceedings of SPIE, Aug 18, 2005

Research paper thumbnail of High temperature intergranular crack growth processes in copper and copper with 1 wt% antimony

Acta Metallurgica, May 1, 1985

ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K u... more ABSTRACT Creep crack growth in Cu and Cu + 1 wt% Sb has been studied at temperatures near 773 K under various loading conditions. The presence of Sb in Cu facilitates brittle intergranular fracture at low temperatures and permits a study of cavitation at the crack tip using SEM techniques. Steep gradients in cavitation damage are observed under constant load conditions wherein the crack accelerates in the course of growth. With a constant stress intensity factor, the crack decelerates during growth and the cavitation spreads evenly over the ligament ahead of the crack tip. The crack growth rate is compared with the stress intensity factor and C*, which have been determined for different loading conditions. Results similar to those of Landes and Begley were obtained, indicating that C*, evaluated experimentally, correlates with crack growth rate under constant displacement rate conditions. Crack growth under constant displacement rate conditions can be described by a simple steady state model.

Research paper thumbnail of An evaluation of quantitative percussion diagnostics for determining the probability of a microgap defect in restored and unrestored teeth: A prospective clinical study

Journal of Prosthetic Dentistry, May 1, 2023

Research paper thumbnail of Quantitative percussion diagnostics for evaluating porosity and surface roughness of cold sprayed and laser deposited materials

Journal of materials research and technology, Sep 1, 2021

Abstract Quantitative percussion diagnostics (QPD) is a non-destructive evaluation method that ha... more Abstract Quantitative percussion diagnostics (QPD) is a non-destructive evaluation method that has been used successfully in a number of applications. This technique involves a rod that is actuated to impact a specimen with a given amount of kinetic energy and the resulting mechanical response of the specimen as a function of time is measured using a piezoelectric force sensor. The mechanical energy returned to the rod is then analyzed. Because contact with the specimen is on the order of a few hundred microseconds, QPD can be used in situations and for specimen conditions (e.g. high temperature) that are not feasible for other nondestructive testing methods. The objective of the present study was to evaluate the use of QPD for characterization of defects in specimens fabricated using two additive manufacturing methods, i.e. cold spray deposition and laser powder directed energy deposition (LPDED). Cold spray specimens were produced using commercially pure nickel with varied process conditions including gas type (i.e. helium and nitrogen) and deposition rate. In addition, a Ti–6Al–4V specimen was manufactured using LPDED with varying porosity content. All specimens were characterized using both QPD and destructive methods (i.e. cross-sectional metallography) to compare results for observed defect characteristics. Cold spray specimens exhibited a lower energy return when they contained more porosity and/or surface roughness. Microscopic plastic deformation at highly porous surfaces was indicated during percussion testing that reached a saturation level after repeated percussion. Overall, the results showed that QPD can effectively evaluate cold spray and LPDED specimens for porosity and surface roughness.

Research paper thumbnail of The Effect of Heat Treatment on the Corrosion Resistance of 440C Stainless Steel in 20% HNO<SUB>3</SUB> + 2.5% Na<SUB>2</SUB>Cr<SUB>2</SUB>O<SUB>7</SUB> Solution

Journal of Materials Engineering and Performance, Apr 1, 2003

The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated... more The effect of heat treatment on the corrosion resistance of 440C stainless steel was investigated in a 20% HNO3 + 2.5% Na2Cr2O7 solution using electrochemical noise (ECN) measurements, electrochemical impedance spectroscopy (EIS), and scanning electron microscopy (SEM) examinations. The noise resistance (Rn), which has been found to be inversely related to the localized corrosion rate, was measured to be 5.7E

Research paper thumbnail of Interaction of Calcium Carbonate with Nanobubbles Produced in an Alternating Magnetic Field

ACS Applied Materials & Interfaces, Aug 31, 2020

Research paper thumbnail of Creep and fracture of engineering materials and structures : proceedings of the Seventh International Conference held at the University of California, Irvine, August 10-15, 1997

Minerals, Metals & Materials Society eBooks, 1997

Research paper thumbnail of The Effect of Electrical Discharge Machining on Electro-Deposited Nano-Crystalline Ni Sheet

Microscopy and Microanalysis, Aug 1, 2007

Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Fl... more Extended abstract of a paper presented at Microscopy and Microanalysis 2007 in Ft. Lauderdale, Florida, USA, August 5 – August 9, 2007

Research paper thumbnail of Characterization of Low-cycle Fatigue Damage in Inconel 718 by Laser Light Scanning

Journal of Materials Research, Aug 1, 1997

Research paper thumbnail of Change of structure, creep fatigue behaviour and life of X 20 CrMoV 12 1

Research paper thumbnail of Reduction of calcified plaque volume in ex vivo pericardial tissue, with nanobubbles

Colloids and Surfaces B: Biointerfaces

Research paper thumbnail of Scanning Laser Detection of Crack Precursors in High RAP Content Asphalt Mixture with Improved Fatigue Performance

Formation of microcracks under fatigue conditions is a complex mechanism and difficult to detect.... more Formation of microcracks under fatigue conditions is a complex mechanism and difficult to detect. A microcrack is not apparent until late in fatigue life of the section. However, structural changes and microcracks can occur earlier and could be used as an originator for fatigue crack formations that lead to failure. Therefore, it is important to develop methods to promptly detect microcracks early in fatigue life well in advance of macrocrack growth. This paper presents the test procedure and analysis approach developed for a non-contact Scanning Laser Detection (SLD) for capturing and monitoring cracks in asphalt mixtures. The study focuses on utilizing SLD to investigate damage resistance of asphalt mixtures containing high Recycled Asphalt Pavement (RAP) content. Use of more RAP in asphalt materials is becoming increasingly popular due to the economic and environmental benefits of recycled materials. On the other hand, stiffer mixes resulting from RAP addition has raised concern ...

Research paper thumbnail of NANO HIGHLIGHT Ideal Strength and Nanomechanics