挤压出口高度对7075/6061复合铸锭组织与性能的影响  

Effects of Extrusion Height on Microstructure and Properties of 7075/6061 Composite Ingot

作　　者：郑小平 谢文杰 曹通 肖广耀 田亚强 陈连生 ZHENG Xiaoping;XIE Wenjie;CAO Tong;XIAO Guangyao;TIAN Yaqiang;CHEN Liansheng(Key Laboratory of Ministry of Education for Modern Metallurgy Technology,North China University of Science and Technology,Tangshan 063210,China;Tangshan Nedium Thick Plate Co.,Ltd.,Tangshan 063600,China)

机构地区：[1]华北理工大学教育部现代冶金技术重点实验室,河北唐山063210 [2]唐山中厚板材有限公司,河北唐山063600

出　　处：《热加工工艺》2024年第22期94-97,共4页Hot Working Technology

基　　金：国家自然科学基金项目(51474091);河北省高等学校科学技术研究项目(ZD2018242)。

摘　　要：采用挤压复合铸造工艺制备出具有半固态组织/枝晶组织的7075/6061双金属复合铸锭。研究了7075铝合金半固态坯料的不同挤压出口高度对复合铸锭界面组织形貌及硬度的影响。研究表明:随着挤压高度减小,界面瞬时结合温度升高,导致复合界面宽度显著增加;界面处组织较细小,且存在合金元素对流扩散行为,致使其硬度高于两侧金属。但当挤压高度较小时,界面组织受热影响剧烈,晶粒严重粗化,导致界面强度整体下降。因此,挤压高度为250mm时,复合铸锭界面组织形貌较好,为细小等轴晶与α-Al固相颗粒较均匀分布,界面硬度较高且过渡平滑。7075/6061 bimetal composite ingot with semi-solid structure/dendrite structure was prepared by squeeze composite casting process.The effects of of different extrusion outlet height of 7075 aluminum alloy semi-solid billet on the interfacial microstructure and hardness of composite ingot was studied.The results show that,with the decrease of extrusion height,the instantaneous bonding temperature of the interface increases,which leads to a significant increase in the width of the composite interface.The microstructure at the interface is fine,and there is convection diffusion behavior of alloy elements,which makes the hardness of the composite interface higher than that of the metals on both sides.However,when the extrusion height is smaller,the thermal effect on the interface structure is severe and the grain coarsening is serious,resulting in the overall decrease of the interface strength.Therefore,when the extrusion height is 250 mm,the microstructure of the composite ingot interface is better,which is fine equiaxed grains andα-Al solid particles are evenly distributed,the interface hardness is higher and the transition is smooth.

关 键 词：固/液复合铸造 半固态 界面组织 元素偏析 

分 类 号：TB331[一般工业技术—材料科学与工程] TG146[金属学及工艺—金属材料]