Microstructure and mechanical properties of Mg-Si alloys processed by cyclic closed-die forging  

循环闭式模锻制备Mg-Si合金的组织和力学性能(英文)

作　　者：J.METAYER 叶兵[1,3] 郭炜[1,3] 王渠东[1,3] 周浩[1,3] F.MOLLET 

机构地区：[1]上海交通大学轻合金精密成型国家工程研究中心,上海200240 [2]Arts et Métiers ParisTech engineering school [3]上海交通大学金属基复合材料国家重点实验室,上海200240

出　　处：《Transactions of Nonferrous Metals Society of China》2014年第1期66-75,共10页中国有色金属学报（英文版）

基　　金：Projects(50674067,51074106)supported by the National Natural Science Foundation of China;Project(2011BAE22B01-5)supported by the National Key Technologies R&D Program during the 12th Five-Year Plan Period,China;Project(09JC1408200)supported by the Science and Technology Commission of Shanghai Municipality,China

摘　　要：Mg-xSi （x=0, 1.5, 3.3） alloys were fabricated and subjected to cyclic closed-die forging （CCDF）, a new severe plastic deformation process, at 450 ℃ for 1, 3, and 5 passes. With applying CCDF, tensile strength, elongation and hardness increase, while coarse Mg2Si particles break into smaller pieces and exhibit more uniform distribution. Mg-1.5%Si alloy exhibits a combination of improved strength and elongation after 5 passes of CCDF processing. The tensile strength is about 142 MPa and elongation is about 8%. The improvement in mechanical properties was further characterized by dry sliding wear testing. The results show that wear resistance improves with silicon content and CCDF process passes, particularly the first pass. The wear resistance increases by about 38% for Mg-3.3%Si after 5 passes of CCDF compared with pure Mg. The improvement of wear is related to microstructure refinement and homogenization based on the Archard equation and friction effect.首先制备Mg-xSi(x=0,1.5,3.3)合金,再采用一种新的大塑性变形方法——循环闭式模锻(CCDF)在450°C进行1、3和5道次加工。通过循环闭式模锻,粗大的Mg2Si颗粒被破碎成小块并且分布更加均匀,材料的拉伸强度、伸长率和硬度得到了提高。经5道次加工后Mg-1.5%Si合金的强度和伸长率同时得到提高,拉伸强度达142 MPa,伸长率为8%。采用干滑动摩擦进一步表征材料性能。结果表明,随着Si含量和加工道次的增加,材料的耐磨性能得到了提高,加工1道次后显著提高,再继续增加道次时提高不明显。经5道次加工后,Mg-3.3%Si合金的耐磨性比纯镁的高38%。根据Archard方程和摩擦效果,耐磨性的提高归结于组织的细化和均匀化。

关 键 词：MG2SI magnesium alloy MG2SI cyclic closed-die forging WEAR MICROSTRUCTURE 

分 类 号：TG319[金属学及工艺—金属压力加工]