含Gd的Mg-Al系合金研究现状  

Research Progress of Mg-Al Based Alloys Containing Gd Element

作　　者：钟诗宇 张丁非[1,2] 胥钧耀[1,2] 赵阳 冯靖凯 蒋斌[1,2] 潘复生[1,2] 杨静波 ZHONG Shiyu;ZHANG Dingfei;XU Junyao;ZHAO Yang;FENG Jingkai;JIANG Bin;PAN Fusheng;YANG Jingbo(College of Materials Science and Engineering,Chongqing University,Chongqing 400045,China;National Engineering Research Center for Magnesium Alloys,Chongqing University,Chongqing 400044,China;HBIS Group Technology Research Institute,Shijiazhuang 050023,China)

机构地区：[1]重庆大学材料科学与工程学院,重庆400045 [2]重庆大学国家镁合金材料工程技术研究中心,重庆400044 [3]河钢集团钢研总院,石家庄050023

出　　处：《材料导报》2021年第9期9016-9027,9032,共13页Materials Reports

基　　金：国家重点研发计划项目(2016YFB0301101);国家自然科学基金重点项目(U1764253)。

摘　　要：镁合金作为"21世纪绿色环保工程材料",具有广阔的应用前景。在诸多类型的镁合金中,Mg-Al系合金是目前应用范围最广、牌号最多的镁合金。合金化一直是改善镁合金性能的重要手段,在围绕Mg-Al系合金开展的众多合金化研究中,加入稀土元素Gd是一个重要的研究方向。近年来,许多研究者围绕微观形貌、力学性能与腐蚀行为三个方面对含Gd的Mg-Al系合金广泛开展了研究。在Mg-Al系合金中加入Gd后,合金第二相的种类与结构会发生相应的变化。其中,最常见的变化为脆性第二相Mg_(17)Al_(12)转换为高硬度第二相Al_(2)Gd。Al_(2)Gd在合金凝固时可作为非均质形核点,使合金的晶粒尺寸得到明显的细化,力学性能也得到提高(细晶强化)。此外,Al_(2)Gd作为热稳定相,在随后的热处理及热加工过程中,不会发生回溶或分解,因此其可以钉扎晶界,抑制晶粒异常长大。2011年有学者首次在含Gd的Mg-Al系合金中发现了LPSO相,但相比于Mg-Zn合金,目前Mg-Al系合金中关于LPSO的研究还比较少,LPSO相的潜力还未得到充分发挥。一般而言,Gd可提升铸态Mg-Al系合金的力学性能,但其对热处理态及热挤压态Mg-Al系合金力学性能的影响更为复杂,还需进一步探究。腐蚀行为方面,加入Gd不仅可以减少Mg-Al系合金晶界处Cu、Fe、Ni等有害杂质元素的偏析,抑制有害杂质元素带来的腐蚀,还可以使腐蚀产物膜更加稳定、致密,从而减缓腐蚀。当然,加入Gd后,Mg-Al系合金第二相的成分、含量、形态及分布发生了改变,导致第二相与基体相的电位差、第二相起到屏蔽腐蚀离子的作用发生改变,也会使合金的腐蚀行为发生相应变化。本文综述了国内外含Gd的Mg-Al系合金的研究现状,介绍了Gd对Mg-Al系合金微观形貌、力学性能和腐蚀行为的影响,并分析了目前研究的不足,最后展望了含Gd的Mg-Al系合金的研究趋势。As an environmentally friendly engineering material in the 21st century,magnesium alloys show a great application prospect.Among various magnesium alloys,Mg-Al based magnesium alloys are the most widely used at present.Alloying has always been a significant method to improve the properties of magnesium alloys.In many studies about Mg-Al based alloys,the addition of rare earth element Gd is an important research direction.In recent years,many researchers have carried out extensive studies on the microstructure,mechanical properties and corrosion behavior of Mg-Al-Gd alloys.In fact,when Gd is added to Mg-Al based alloys,the type and structure of the second phase would change with different Gd content.The most common one is the transformation from brittle second phase Mg_(17)Al_(12) to high hardness second phase Al 2Gd.The latter could act as a heterogeneous nucleation point during solidification.Additionally,it is thermally stable and would not dissolve or decompose in the subsequent heat treatment and hot working process.In other words,Al 2Gd could increase the nucleation rate,pin the grain boundary and restrain the abnormal grain growth.As a result,the grain size of the alloy is obviously refined and the mechanical properties are improved(fine grain strengt-hening).In 2011,some scholars found LPSO phase in Mg-Al based alloys containing Gd for the first time.However,compared with Mg-Zn alloy,the research on LPSO in Mg-Al based alloys is still relatively rare,and the strengthening effect of LPSO phase has not been fully utilized.Generally,Gd can improve the mechanical properties of as-cast Mg-Al based alloys.But its effect on those of Mg-Al based alloys which subjected to heat treatment and/or hot deformation are more complex.Hence,further works are supposed to be carried out.In terms of corrosion behavior,the addition of Gd can reduce the segregation of harmful impurity elements such as Cu,Fe,Ni at the grain boundary.Besides,a much denser corrosion film could be achieved by adding Gd.Furthermore,the composition,co

关 键 词：Mg-Al系合金 GD 微观形貌 力学性能 腐蚀行为 

分 类 号：TG146.2[一般工业技术—材料科学与工程]