ECAP过程中不同形态的Mg_2Si相演变规律及合金性能研究  

Evolution Law of Mg_2Si Phase with Different forms and Study on Properties of Alloy in ECAP Process

作　　者：周丽丹[1,2] 张增耀[3] 王红霞[3] 

机构地区：[1]山西中能建电力装备有限公司,山西太原030031 [2]山西职业技术学院,山西太原030006 [3]太原理工大学材料科学与工程学院,山西太原030024

出　　处：《热加工工艺》2017年第15期53-56,60,共5页Hot Working Technology

基　　金：国家自然科学基金项目(51301118);山西省高等学校科技创新项目(2013108)

摘　　要：采用金属型铸造分别制备了具有汉字状Mg_2Si相的Mg-10Al-2.1Si合金和具有骨骼状的Mg_2Si相的Mg-8.8Al-0.77Si合金,并对两种合金进行了4道次等通道挤压。对比研究了两种合金中Mg_2Si相的演变规律,分析了其碎化机制及其对合金室/高温性能的影响。结果表明,ECAP挤压后,粗大汉字状Mg_2Si相碎化程度较小,内部产生裂纹,合金室/高温性能并没有明显的提高;骨骼状Mg_2Si相更易被挤压碎化成小颗粒,并均匀分布在基体上,使得合金的室/高温性能得到了显著提高。两种铸态合金的高温稳定性比较好,耐高温的Mg_2Si增强相在高温时钉扎晶界和网状Mg_(17)Al_(12)相作用显著。Mg2Si phase with Chinese character in Mg-10Al-2.1Si alloy and Mg2Si phase with skeleton like in Mg- 8.8Al-0.77Si alloy were prepared by metal mould casting. Equal-channel angular pressing （ECAP） with 4-passes of two kinds of alloy was carded out. The evolution of Mg2Si phase in two alloys was compared and studied. The fragmentation mechanism and its influence on room/high temperature properties of the alloy were analyzed. The results show that after the ECAP extrusion, the coarse Chinese characters of Mg2Si phase are less fragmented, internal cracks occur, and the alloy room/high temperature properties have not improved significantly; the skeletal shaped Mg2Si phase is more easily extruded, brekens into smaller particles and is uniformly distributed on the substrate, so that the room/high temperature properties of the alloy are significantly improved. The two kinds of as cast alloys have better stability at high temperature. Mg2Si reinforced phase of high temperature resistant has obvious effect on pinning grain boundary and network Mg17Al12 phase at high temperature.

关 键 词：MG2SI相 等通道转角挤压 碎化机制 力学性能 

分 类 号：TG379[金属学及工艺—金属压力加工] TG113.25