摘要
为研究热加工工艺参数对钛合金塑性成形过程中微观组织的影响,利用Gleeble-3500型热模拟试验机对BT25钛合金进行单道次等温恒应变压缩试验。分析真应力-应变曲线,建立JMAK动态再结晶动力学方程;通过对热变形行为的分析,推导出钛合金的位错密度模型、再结晶形核和晶粒长大模型;结合元胞自动机的算法,建立元胞自动机(Cellular automata,CA)模型并利用该模型模拟和验证了BT25钛合金热变形过程中动态再结晶行为。结果表明,BT25钛合金的流动应力对应变速率和变形温度非常敏感;提高变形温度或降低应变速率均有利于材料发生动态再结晶;CA模型模拟晶粒尺寸误差约为3%,预测DRX体积分数误差在10%以内。该模型具有良好的预测精度,为合金材料在塑性加工过程中优化工艺参数和控制锻件微观组织演变提供了可靠性依据。
In order to study the effect of thermal processing parameters on microstructure of titanium alloy during plastic forming,the single-pass isothermal constant strain compression test of BT25 titanium alloy is carried out by Gleeble-3500 thermal simulation machine.The true stress-strain curves are analyzed and the dynamic equation of JMAK recrystallization is established.Based on analysis of thermal deformation behavior,dislocation density model,recrystallization nucleation model and grain growth model are derived.A cellular automata(CA)model is established through the algorithm to simulate and verify the dynamic recrystallization(DRX)behavior of BT25 titanium alloy during thermal deformation.The results show that the flow stress of BT25 titanium alloy is very sensitive to the strain rate and deformation temperature.Increasing deformation temperature or decreasing strain rate is beneficial to dynamic recrystallization of materials.The CA model simulated the grain size about the error is 3%,and predicted the DRX volume fraction about error within 10%.This model has good prediction accuracy.A reliable basis is provided for optimizing technological parameters and controlling microstructure evolution of forging in the process of plastic machining.
作者
冯瑞
王克鲁
鲁世强
李鑫
欧阳德来
周璇
钟明君
FENG Rui;WANG Kelu;LU Shiqiang;LI Xin;OUYANG Delai;ZHOU Xuan;ZHONG Mingjun(School of Aerospace Manufacturing Engineering,Nanchang Hangkong University,Nanchang 330063;School of Materials Science and Engineering,Nanchang Hangkong University,Nanchang 330063)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2020年第20期66-73,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(51761029,51864035)
江西省研究生创新专项资金(YC2019-S337)资助项目。
关键词
BT25钛合金
热变形
动态再结晶
元胞自动机
数值模拟
BT25 titanium alloy
thermal deformation
dynamic recrystallization
cellular automata
numerical simulation
