新型优质GH738合金热变形过程动态再结晶模型的建立  

Dynamic Recrystallization Model Analysis of New Type High Quality GH738 Alloy during Its Hot Deformation Processes

作　　者：郭晶 牛文龙 马思文 张麦仓[1] GUO Jing;NIU Wenlong;MA Siwen;ZHANG Maicang(School of Materials Science and Engineering,University of Science and Technology Beijing,Beijing 100083)

机构地区：[1]北京科技大学材料科学与工程学院,北京100083

出　　处：《机械工程学报》2022年第10期59-67,共9页Journal of Mechanical Engineering

基　　金：国家自然科学基金(51971016);科技部重大专项(2021YFB3700403)资助项目。

摘　　要：采用MTS810-25T低周疲劳试验机对新型优质GH738合金进行热压缩试验,分析该合金在不同初始晶粒尺寸(42~340μm)、变形温度(1020~1100℃)、应变速率(0.01~1 s^(-1))和应变量(0.15~0.70)条件下的动态再结晶(Dynamic recrystallization,DRX)组织演化规律,并利用Avrami方程构建了该合金的动态再结晶模型,进而结合DEFORM软件及热压缩试验进行验证。结果表明,随着初始晶粒尺寸的减小,应变速率的降低,变形温度升高,应变量增加,动态再结晶的体积分数增加;有限元结果及验证试验均表明,建立的新型优质GH738合金的动态再结晶临界应变模型、体积分数模型以及晶粒尺寸模型,具有良好的预测精度。Series hot compression tests of the new type alloy of high-quality GH738 were carried out under low-cycle fatigue tester of MTS810-25T,the microstructure evolution of dynamic recrystallization(DRX)for this alloy under different hot deformation conditions,including initial grain sizes(range of 42-340μm),temperature(range of 1020-1100℃),strain rate(range of 0.01-1 s^(-1)),and engineering strain(range of 0.15-0.70)was systematically investigated.Then,series Avrami-type model of its dynamic recrystallization was established.The verification of the dynamic recrystallization model by numerical simulation using DEFORM software and typical compression test was conducted.The results show as follows:The volume fraction for the new type alloy of high-quality GH738 during dynamic recrystallization processes increases with the decrease of initial grain size,the decrease of strain rate,and increasing of the deformation temperature and strain.Based on the quantitative metallography and nonlinear fitting method,the critical strain model,volume fraction model and grain size model of the new type alloy of high-quality GH738 were established.Coupled the above established dynamic recrystallization model of the new type alloy of high-quality GH738 in finite analysis software of DEFORM,and contracted the simulation results to typical compression test,indicate that the dynamic recrystallization model for this alloy can provide effective prediction for microstructure control in actual hot working process.

关 键 词：新型优质GH738合金 热变形 组织演化 动态再结晶模型 

分 类 号：TG132[一般工业技术—材料科学与工程]