喷射成形超高强铝合金热压缩过程中的流变行为  

Flow Stress Behavior of Spray-Formed Ultra-high Strength Aluminum Alloy during Compression at Elevated Temperature

作　　者：孙鹏[1] 李志辉[1] 熊柏青[1] 张永安[1] 李锡武[1] 刘红伟[1] 王锋[1] 

机构地区：[1]北京有色金属研究总院有色金属材料制备加工国家重点实验室,北京100088

出　　处：《航空材料学报》2014年第3期8-14,共7页Journal of Aeronautical Materials

基　　金：国家重点基础研究发展计划项目资助(2011CB606303;2012CB619504)

摘　　要：采用Gleeble3500热模拟试验机进行热压缩试验，研究了经热等静压（HIP）致密化的喷射成形Al—10．8Zn．2．8Mg．1．9cu-0．12Zr铝合金锭坯的流变应力行为。采用线性拟合的方法建立了合金的本构方程与热加工图，利用背散射电子衍射技术（EBSD）表征了变形条件下热压样品的微观组织。结果表明，喷射成形铝合金具有较高的变形激活能，但加工性相对较差，合适的加工温度为380～405℃，应变速率不宜超过0．5s^-1；变形温度和应变速率对合金的流变应力有非常显著的影响，合金峰值应力随变形温度的升高而降低，随应变速率的增加而增加；高应变速率和较低温度有利于形成并保留更多的亚晶结构。The Al-10.8Zn-2.8Mg-1.9Cu-0.12Zr aluminum alloy preforms were prepared by spray forming technology and subsequently processed by hot isostatic pressing （ HIP）. The flow stress behavior of the alloy during hot deformation was investigated by isothermal compression tests using Gleeble-3500 system in the temperature range from 340℃ to 430℃ and at strain rate range from 0.01s^-1 to 10s^-1. The constitutive equation and the processing maps were evaluated by linear regression analysis. The electron back scattered diffraction technique（EBSD） was employed to analyze the microstructure of the alloy pressed under various deformation conditions. The results show that the deformation activation energy Q of spray-formed Al-Zn-Mg-Cu alloy is higher than that of other Al-Zn-Mg-Cu alloyprepared by ingot metallurgy, processability is relatively poor, the suitable deformation temperature ranges from 380℃ to 405℃ and the strain rate should be below 0.5s^-1. The flow stress of the alloy is significantly influenced by the strain rate and deformation temper- ature, the peak of flow stress decreases with increasing temperature and increases with a rise in strain rate, a higher strain rate and lower temperature are benefit to the formation of sub-grains microstructure.

关 键 词：喷射成形铝合金 热流变行为 本构方程 EBSD 热加工图 

分 类 号：TG166.3[金属学及工艺—热处理]