弥散铜/35Cr电触头材料的热变形行为

Hot deformation behavior of dispersion copper/35Cr electrical contact composite

通过快速热压烧结和内氧化法相结合制备了Al_(2)O_(3)-Cu/35Cr复合材料,在变形温度和试验速率分别为650~950℃和0.001~1 s^(-1)下,采用Gleeble−1500D型试验机对材料进行热变形试验,通过其真应力−真应变曲线分析了两种试验参数对流变应力的影响,并构建了复合材料的本构方程和热加工图,分析其热加工参数。结果表明:复合材料的Cr颗粒均匀分布在纳米γ-Al_(2)O_(3)弥散强化Cu基体上,其烧结态致密度、导电率和显微硬度分别为98.9%、44.4%IACS和145HV。Al_(2)O_(3)-Cu/35Cr复合材料具有热敏感性和正应变速率相关性,并且在变形量为0.3~0.5时最佳变形温度和应变速率参数分别为650~680℃、0.55~1 s^(-1)和810~950℃、0.007~0.123 s^(-1)。

Al_(2)O_(3)-Cu/35Cr composite was prepared by the combination process of fast hot-press sintering and internal oxidation.The composite was isothermally compressed using Gleeble−1500D testing machine under the experimental conditions of the deformation temperature and strain rate set at 650−950℃and 0.001−1 s^(-1),respectively,and their true stress-true strain curves were plotted to analyze the effects of the two test parameters on the flow stress.Meanwhile,the constitutive equation and hot processing map of the composite were constructed to analyze their hot processing parameters.The results show that the Cr particles of the composite are uniformly distributed on the nanoγ-Al_(2)O_(3)dispersion-strengthened Cu matrix,and the sintered density,conductivity and microhardness are 98.9%,44.4%IACS and 145HV,respectively.The Al_(2)O_(3)-Cu/35Cr composite has thermal sensitivity and positive strain rate correlation.And the optimum deformation temperature and strain rate parameters at deformations of 0.3 to 0.5 are in the intervals of 650 to 680℃,0.55 to 1 s^(-1)and 810 to 950℃,0.007 to 0.123 s^(-1).