Mg15Al镁合金ECAP变形过程中β相的碎化机理及动态析出行为  

Fragmentation mechanism and dynamic precipitation behavior of β phase in Mg15Al magnesium alloy during ECAP

作　　者：王红霞[1,2] 周康康[1,2] 梁伟[1,2] 龚家林[1,2] 曹晓卿[1] 赵兴国[1,2] 

机构地区：[1]太原理工大学材料科学与工程学院,太原030024 [2]太原理工大学新材料界面科学与工程教育部重点实验室,太原030024

出　　处：《中国有色金属学报》2011年第8期1794-1800,共7页The Chinese Journal of Nonferrous Metals

基　　金：山西省青年科技研究基金资助项目(2008021033);太原市明星专项基金资助项目(09121002);山西省自然科学基金资助项目(2010011033-1);山西高校科技研究开发项目(2007110)

摘　　要：为了改善Mg-Al系合金中β-Mg17Al12相的形态、大小和分布,充分发挥其沉淀强化作用,利用能产生强塑性变形的等通道转角挤压法挤压Mg15Al高铝镁合金;采用XRD、SEM、EDS和TEM研究不同道次ECAP挤压后Mg15Al高铝镁合金中β-Mg17Al12相的演变。结果表明:ECAP强塑性变形能够有效地碎化Mg15Al高铝镁合金中粗大的网状共晶β-Mg17Al12相;随挤压道次的增加,β-Mg17Al12相尺寸逐渐减小,挤压4道次后,网状共晶β-Mg17Al12相被破碎成尺寸在5μm以下的小块,分布得到一定改善;由于高应力与高温的共同作用,挤压2道次后,部分β-Mg17Al12相发生回溶,挤压4道次后,在α-Mg基体中动态析出许多尺寸在200 nm以下的粒状β-Mg17Al12相。In order to improve the morphology,size and distribution of β-Mg17Al12 phase in the Mg-Al alloy and fulfill the precipitation strengthening effect of β-Mg17Al12 phase,Mg15Al high-aluminum magnesium alloy was processed by equal channel angular pressing.The evolution of β-Mg17Al12 phase in the Mg15Al high-aluminum magnesium alloy after equal channel angular pressing（ECAP） for different passes was investigated by XRD,SEM,EDS and TEM.The results show that the coarse network eutectic β-Mg17Al12 phase in Mg15Al high aluminum-magnesium alloy can be effectively fragmentized by ECAP.With increasing extrusion passes,the size of β-Mg17Al12 decreases.After ECAP for 4 passes,β phase is fragmentized into small lump-shaped particles with size of less than 5 μm and the distribution of β phase becomes more homogeneous.Meanwhile,due to the large shear stress and high temperature,the dissolution of β phase in matrix occurs after ECAP for 2 passes and a large number of granular β phase with the size below 200 nm precipitates from the matrix after ECAP for 4 passes.

关 键 词：Mg15Al高铝镁合金 β-Mg17Al12相 碎化机理 动态析出行为 

分 类 号：TG146.2[一般工业技术—材料科学与工程]