Stress Relaxation Behavior of Al_2O_3/ Cu Dispersion Strengthened Copper Alloy

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Stress Relaxation Behavior of Al_2O_3/ Cu Dispersion Strengthened Copper Alloy

Journal Title: 河南科技大学学报（自然科学版） - Year 2017, Vol 38, Issue 1

Abstract

The stress relaxation behavior of Al_2O_3/Cu dispersion strengthened copper alloy at different temperature( room temperature,100 ℃,200 ℃ and 300 ℃) was studied by the stress relaxation experiment.The test data were fitted by twice delay function. Based on the experimental stress relaxation curves,the relationship between plastic strain rate and stress was derived. The result shows that the stress relaxation curve is divided into two stages. The residual stress decreases rapidly at the first stage. The residual stress decreases slower at the second stage,and approaches stress relaxation limit along with the time delaying. The higher the temperature,the lower the stress relaxation limit is. When the temperature is at room temperature and 100 ℃,the residual stress decay rate is 30. 7% and 30. 3% respectively. And when the temperature at 200 ℃ and300 ℃,the residual stress decay rate is 92. 4% and 97. 3% respectively. So the service temperature of the alloy material used as the elastic element should be less than 100 ℃. Plastic strain rate-stress curves are composed of high stress stage and low stress stage,and a threshold stress is found between the two stages. Thehigher the temperature,the lower the threshold stress is. The stress relaxation mechanism of different threshold stress is different. The stress relaxation mechanism is enhanced by the second phase particles at room temperature and 100 ℃,and the dislocation climbing mechanism is at 200 ℃ and 300 ℃.

Authors and Affiliations

Yayong ZHAO, Yanmin ZHANG, Kexing SONG

Keywords

Al2O3/Cu dispersion strengthened copper alloy; stress relaxation; curve fit; threshold stress;

EP ID EP477818
DOI -
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