Al_2O_3/Cu弥散强化铜合金应力松弛行为  

Stress Relaxation Behavior of Al_2O_3/ Cu Dispersion Strengthened Copper Alloy

作　　者：赵亚永[1] 张彦敏[1,2] 宋克兴[1,2] 

机构地区：[1]河南科技大学材料科学与工程学院,河南洛阳471023 [2]河南科技大学有色金属共性技术河南省协同创新中心,河南洛阳471023

出　　处：《河南科技大学学报（自然科学版）》2017年第1期6-9,14,共5页Journal of Henan University of Science And Technology:Natural Science

基　　金：国家自然科学基金项目(U1502274);河南省高校科技创新团队支持计划基金项目(14IRTSTHN007);河南省国际合作基金项目(162102410025)

摘　　要：通过应力松弛试验,研究了Al_2O_3/Cu弥散强化铜合金在不同温度(室温、100℃、200℃和300℃)下的应力松弛行为。应用二次延迟函数模型拟合了应力松弛曲线,推导了不同温度下材料塑性应变速率与应力的关系。研究结果表明:Al_2O_3/Cu弥散强化铜合金的应力松弛曲线分为两个阶段。第一阶段,残余应力迅速下降;第二阶段,残余应力缓慢下降,随着时间延长无限接近应力松弛极限,且温度越高,应力松弛极限越低。在室温和100℃时,残余应力衰减率分别为30.7%和30.3%;在200℃和300℃时,残余应力衰减率分别为92.4%和97.3%。因此,该合金材料作为弹性元件时服役温度应小于100℃。塑性应变速率与应力关系曲线可以分为高应力和低应力阶段,两个阶段之间存在门槛应力,温度越高,门槛应力越小。门槛应力不同,相应的应力松弛机制也不同,室温和100℃时为第二相颗粒增强机制;200℃和300℃时为位错攀移机制。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 ℃.

关 键 词：Al2O3/Cu弥散强化铜合金 应力松弛 曲线拟合 门槛应力 

分 类 号：TG146.1[一般工业技术—材料科学与工程]