(1. 河南科技大學(xué) 材料科學(xué)與工程學(xué)院，洛陽(yáng) 471003；2. 河南科技大學(xué) 河南省耐磨材料工程技術(shù)研究中心，洛陽(yáng)471003；3. 洛陽(yáng)高科鉬鎢材料有限公司，洛陽(yáng)471000)
摘 要: 采用Gleeble−1500熱模擬機(jī)，在變形溫度為1 100～1 350 ℃、變形速率為0.01～5 s−1、變形量為60％的實(shí)驗(yàn)條件下，對(duì)純鉬板坯的高溫塑性變形行為進(jìn)行研究。結(jié)果表明：流變應(yīng)力隨變形溫度的升高而減小，隨應(yīng)變速率的增大而增大；不同變形溫度下流變應(yīng)力之間的差值隨著應(yīng)變速率的增加逐漸減小；同一應(yīng)變速率下，峰值應(yīng)力隨變形溫度的升高向應(yīng)變小的方向推移。采用包含Zene-Hollomon參數(shù)的雙曲正弦模型，建立了純鉬板高溫塑性流變應(yīng)力與變形溫度和應(yīng)變速率之間的本構(gòu)方程。依據(jù)本構(gòu)方程計(jì)算出的純鉬板坯流變應(yīng)力理論值與實(shí)際值的平均相對(duì)誤差僅為3.68％，表明該本構(gòu)方程可為純鉬熱成形加工工藝的制定提供理論依據(jù)。
關(guān)鍵字: 純鉬板坯；熱模擬；流變應(yīng)力；本構(gòu)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
