热等静压TC4粉末体热压缩变形组织演变规律  

Microstructure evolution of hot isostatic pressing TC4 powders during hot compression

作　　者：任璐英 张治民[1] 白瑞 马城 薛勇[1] 王强[1] REN Luying;ZHANG Zhimin;BAI Rui;MA Cheng;XUE Yong;WANG Qiang(School of Materials Science and Engineering,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学材料科学与工程学院,山西太原030051

出　　处：《兵器材料科学与工程》2018年第4期58-62,共5页Ordnance Material Science and Engineering

基　　金：国家自然科学基金(51675492)

摘　　要：针对热等静压工艺制备的Ti-6Al-4V合金,利用Gleeble-1500热模拟机进行高温热压缩变形试验,结合OM组织观察研究热变形温度为850~1 050℃与变形速率为0.001~5 s-1对该合金热变形组织的影响规律。结果表明:单道次变形时,当温度在900℃及以下,层片状α相发生球化或动态再结晶,得到均匀等轴的细小组织;高于950℃时,变形后淬火组织由均匀等轴β晶粒与板条马氏体组成,晶粒内有交叉排列的短片层α相;在950℃以下,随着应变速率增大,动态再结晶体积分数降低,晶粒内α相细化,当应变速率过大时,变形后组织以拉长的未再结晶粗大β晶粒为主;相较单道次变形,3道次变形中每一道次变形量较小,低应变速率下再结晶组织易粗大化,随着应变速率的增大,再结晶组织不均匀分布。The high temperature thermal compression test was carried out by using Gleeble-1500 thermal simulator for the Ti-6 Al-4 V alloy prepared by hot isostatic pressing process. The effect of deformation temperature 850-1 050 ℃ and deformation rate0.001-5 s-1 on the microstructure evolution of the alloy was investigated by OM observation. The results show that in the 1-pass compression process,when the temperature is below 900 ℃,the homogeneous fine equiaxed microstructure is obtained due to the spheroidization or dynamic recrystallization of lamellar α. When the temperature is higher than 950 ℃,the microstructure is composed of uniform equiaxed β grains and lath martensite,and the cross-arranged short lamellar α phases are precipitated in the grain. With the increase of strain rate,and the volume fraction of dynamic recrystallized grains decreases and lamellar αphases in the grains are refined at 950 ℃. At high strain rate,the microstructure is mainly consisted of elongated un-recrystallized coarse β grains. Compared with 1-pass compression,the amount of deformation in each pass is small during 3-pass compression process,the recrystallization microstructure becomes coarser at low strain rate and the dynamic recrystallization microstructure is uneven with the increase of strain rate.

关 键 词：热等静压 TC4钛合金 热压缩变形 显微组织 

分 类 号：TF125.22[冶金工程—粉末冶金]