(1. 河南科技大学 材料科学与工程学院，洛阳 471003；2. 河南科技大学 河南省耐磨材料工程技术研究中心，洛阳471003；3. 洛阳高科钼钨材料有限公司，洛阳471000)
摘 要: 采用Gleeble−1500热模拟机，在变形温度为1 100～1 350 ℃、变形速率为0.01～5 s−1、变形量为60％的实验条件下，对纯钼板坯的高温塑性变形行为进行研究。结果表明：流变应力随变形温度的升高而减小，随应变速率的增大而增大；不同变形温度下流变应力之间的差值随着应变速率的增加逐渐减小；同一应变速率下，峰值应力随变形温度的升高向应变小的方向推移。采用包含Zene-Hollomon参数的双曲正弦模型，建立了纯钼板高温塑性流变应力与变形温度和应变速率之间的本构方程。依据本构方程计算出的纯钼板坯流变应力理论值与实际值的平均相对误差仅为3.68％，表明该本构方程可为纯钼热成形加工工艺的制定提供理论依据。
关键字: 纯钼板坯；热模拟；流变应力；本构方程
pure molybdenum plate slab and constitutive equation
（1. College of Materials Science and Engineering, Henan University of Science and Technology, Luoyang 471003, China;
2. Henan Engineering Research Center for Wear of Material,
Henan University of Science and Technology, Luoyang 471003, China;
3. Luoyang Hi-tech Molybdenum and Tungsten Material Company, Luoyang 471000, China）
Abstract:The pyroplastic deformation behavior of pure molybdenum slabs was studied on the Gleeble−1500 thermal-mechanical simulator at 1 100−1 350 ℃ with the rate of deformation 0.01−5 s−1 and the deformation of 60%. The results indicate that the rheological stress is decreased with increasing the temperature, and increased with increasing the rate of deformation. The difference between rheological stresses at different deformation temperatures is decreased with increasing the strain rate. At the same strain rate, the peak stress is moved from high strain to low strain with increasing temperature. The constitutive equation including rheological stress, strain rate and temperature was established by hyperbolic sine model with Zene-Hollomon parameter. Using this equation, the average relative error between the theoretical value and actual value is only 3.68％. The constitutive equation can provide theoretical basis for formulating hot-forming processing of molybdenum sheet.
Key words: pure molybdenum slab; thermal simulation; rheological stress; constitutive equation
