7A04铝合金车轮半成品热变形行为研究  

Hot deformation behavior of semi-finished wheel rims of 7A04 aluminum alloy

作　　者：秦清风[1] 谭迎新[1] 杨勇彪[2] 张治民[2] 

机构地区：[1]中北大学化工与环境学院,山西太原030051 [2]中北大学材料科学与工程学院,山西太原030051

出　　处：《轻合金加工技术》2016年第4期51-57,共7页Light Alloy Fabrication Technology

摘　　要：采用GLEEBLE-1500热模拟试验机研究了7A04铝合金车轮半成品的热变形及最佳热成形参数,使用金相显微镜分析微观组织。结果表明,在变形温度一定时,该铝合金的流变应力随应变速率的增加而逐渐增大;在应变速率一定时,其流变应力随变形温度的升高而降低。当变形温度为320℃时,晶粒仅发生形状的变化,其变形机制以动态回复为主;当变形温度为480℃时,出现了动态再结晶现象,从而使晶粒细化。铝合金车轮半成品热加工图中仅有一个功率耗散较大的区域(370℃~480℃,0.1 s^(-1)~0.003 s^(-1)),且其峰值功率耗散可达37%,失稳区的范围是:380℃~420℃,0.1 s^(-1)~1 s^(-1)。其优化的热加工参数与挤压态棒材及铸态7A04铝合金的优化热加工参数不同,表明多道次变形时,7A04铝合金热加工不宜选择单一的热变形参数。Compression tests were carried out in order to understand the hot deformation behavior and the optimized hot working parameters for the semi-finished 7A04 aluminum alloy rim using GLEEBLE-1500 thermal simulation machine. Optical microscopy was used for microstructure characterization. The results show that the flow stress of the semi finished7A04 aluminum alloy decreases with increasing of temperature when strain rate is certain.The plastic deformation mechanisms are dynamic recovery and dynamic recrystallization at320℃ and 480℃ respectively,the latter makes the grains refined. There is one region at370℃- 480℃,0. 1- 0. 003 s-（-1） with its peak dissipation efficiency as high as 37%. There is one instability deformation domain at 380℃- 420℃ and at 0. 1 s-（-1）- 1 s-（-1） for the semifinished 7A04 aluminum alloy rim. These parameters are different from those of extruded and cast 7A04 aluminum alloy,indicating that invariable hot working parameters might not be the best choice for the parts obtained through multi-passes hot working.

关 键 词：7A04铝合金车轮 本构方程 热加工图 道次 热加工参数 

分 类 号：TG166.3[金属学及工艺—热处理] TG146.21[金属学及工艺—金属学]