30%Cr-Cu复合材料热变形及动态再结晶临界条件  

Hot deformation and critical conditions of dynamic recrystallization of the 30% Cr-Cu composites

作　　者：耿昊[1] 朱顺新[2] 刘勇[2,3] 

机构地区：[1]中国船舶重工集团公司第七一三研究所,郑州450015 [2]河南科技大学材料科学与工程学院,洛阳471023 [3]有色金属共性技术河南省协同创新中心,洛阳471023

出　　处：《复合材料学报》2017年第6期1308-1315,共8页Acta Materiae Compositae Sinica

基　　金：国家自然科学基金(51101052);河南省高校重点科研项目(15A430006)

摘　　要：采用放电等离子烧结法(SPS)制备出30%Cr-Cu复合材料,对其致密度、硬度和导电率等相关性能进行测试,并观察分析该复合材料的显微组织。利用Gleeble-1500D型热模拟试验机在变形温度650~950℃、应变速率0.001~10s-1、变形量60%的条件下对30%Cr-Cu复合材料进行热模拟压缩试验。对热压缩试验得到的真应力-应变数据进行拟合、计算和分析,构建该复合材料的本构方程,同时得到材料的加工硬化率θ,利用材料的lnθ-ε曲线出现有拐点和-(lnθ)/ε-ε曲线对应有最小值这一判据,分析该复合材料的动态再结晶临界条件。结果表明:30%Cr-Cu复合材料的真应力-应变曲线主要以动态再结晶软化机制为特征,峰值应力随应变速率的增加和温度的降低而升高;该复合材料的lnθ-ε曲线出现拐点,-(lnθ)/ε-ε曲线对应有最小值,该最小值所对应的应变为临界应变εc,且εc随变形温度的升高和应变速率降低而减小,εc与Zener-Hollomon参数Z的函数关系为εc=2.38×10-3 Z0.1396。30%Cr-Cu composites were prepared by spark plasma sintering process （SPS）. The basic properties of the composite such as relative density, Brinell hardness and electrical conductivity were tested and the microstructures of the composites were observed. Hot simulation compression tests of the 30%Cr-Cu composites were conducted at deformation temperature of 650--950℃, strain rate of 0. 001--10 s^-1 and deformation amount of 60% by the Gleeble-1500D thermal-mechanical simulation test machine. The true stress-true strain data of the 30% Cr-Cu composites were fitted, calculated and analyzed, constitutive equation of the composites was constructed, and the work hardening rate 0 of the 30%Cr-Cu composite was obtained at the same time. The critical conditions of dynamic recrystallization during hot deformation of the 30%Cr-Cu composites were analyzed by computing the inflection point criterion of Inθ-ε curves and the minimum vaiue criterion of --8 （Inθ）/ε-ε curves. The results show that the true stress-strain curves of the 30%Cr-Cu composites are mainly characterized by dynamic recrystallization softening mechanism. The peak stress increases with the increasing strain rate and the decreasing deformation temperature. The inflection point presents in the In 0-e curve and a minimum value appeas in the corresponding - （Inθ）/ ε-ε curve when the critical state of the 300% Cr-Cu composites is attained, in which the strain that relates to the minimum value is the critical strain εc. The critical strain εc decreases with the increasing deformation temperature and the decreasing strain rate. The model of the critical strain with εc and Zener-Hollomon parameter can be described by the function of εc=2.38×10^-3 Z0.1396.

关 键 词：30%Cr-Cu复合材料 本构方程 加工硬化率 动态再结晶 临界条件 

分 类 号：TB331[一般工业技术—材料科学与工程]