等温重熔7075铝合金微观组织演变及预测研究  

Microstructure Evolution and Prediction of 7075 Aluminum Alloy After Isothermal Remelting

作　　者：张万鹏 郎利辉[1] 臧博 王川 秦成伟 楚伯刚 Zhang Wanpeng;Lang Lihui;Zang Bo;Wang Chuan;Qin Chengwei;Chu Bogang(School of Mechanical Engineering&Automation,Beihang University,Beijing 100191,China;Bogie Technology Center,CRRC Tangshan Co.,Ltd,Tangshan 063000,China)

机构地区：[1]北京航空航天大学机械工程及自动化学院,北京100191 [2]中车唐山机车车辆有限公司转向架技术中心,河北唐山063000

出　　处：《稀有金属材料与工程》2023年第6期2085-2092,共8页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51675029);河北省省级科技计划(21312201D)。

摘　　要：以7075-T651铝合金挤压材为研究对象,研究半固态等温重熔过程中等温温度和保温时间对坯料微观组织的影响,并基于Deform-3D软件JMAK模块中Grain-Growth模型预测液固区间晶粒长大规律。结果表明,随着等温温度和保温时间的增加,晶粒尺寸随之增大,晶粒趋近圆整,液相含量增多。在高固相区间保温时,组织经历了再结晶、合并长大和部分重熔等过程;在低固相区间保温时,组织短时间内即再结晶完全,并迅速长大,长大过程主要以Ostwald熟化机制为主。等温重熔晶粒长大公式中指数值n值取n=3更符合液固区间等温重熔的实际情况。经计算,在不同等温温度下,晶粒长大速度依次为:55.1、295.3、817.9μm^(3)/s。从能量的角度考虑,结合晶粒长大公式,测得试验材料晶粒长大的晶界移动激活能为118.6 kJ/mol,基于此预测了等温温度在550~620℃范围内的晶粒长大规律,预测结果和实际测量结果接近。Taking the as-extruded 7075 Al alloy,material as the research object,the effects of isothermal temperature and holding time on the billet microstructure after semi-solid isothermal remelting built were studied.The grain growth law of solid-liquid area was predicted by the grain-growth model in the JMAK module of DEFORM-3D software.The results show that the grain size is gradually increased,the grain tends to be rounded,and the liquid content of the grain border is increased with increasing the isothermal temperature and prolonging the holding time.During the high solid fraction interval,the grains undergo recrystallization,merging and growth,and the liquid phase increases.In the low solid fraction interval,the non-recrystallized grains are rarely visible,and Ostwald ripening is the primary mechanism for the rapid grain growth.In the semi-solid isothermal remelting grain growth formula,n=3 is a more accurate value.The rate of grain growth is calculated as 55.1,295.3,and 817.9μm^(3)/s with increasing the isothermal temperature.Using the energy relation and grain growth formula,the activation energy of the grain boundary migration of the 7075 Al alloy is calculated as 118.6 kJ/mol.Therefore,a grain growth rule in the range of 550-620℃ can be predicted.The measured and expected values are close to each other.

关 键 词：等温重熔 铝合金 微观组织 模拟预测 

分 类 号：TG146.21[一般工业技术—材料科学与工程]