Sr在耐热镁合金中的应用及研究进展  

Application and Research Progress of Strontium in Heat-resistant Magnesium Alloy

作　　者：张娜 程仁菊 董含武 刘文君[2] 詹俊 蒋斌 潘复生[1,2] ZHANG Na;CHENG Renju;DONG Hanwu;LIU Wenjun;ZHAN Jun;JIANG Bin;PAN Fusheng(Chongqing Academy of Science and Technology,Chongqing 401123;College of Materials Science and Engineering,Chongqing University,Chongqing 400030)

机构地区：[1]重庆市科学技术研究院,重庆401123 [2]重庆大学材料科学与工程学院,重庆400030

出　　处：《材料导报》2019年第15期2565-2571,共7页Materials Reports

基　　金：重庆市重点产业共性关键技术创新专项项目(cstc2017zdcy-zdzxX0006);国家重点研发项目(2016YFB0301100);国家青年科学基金项目(51504052);重庆市基本科研业务费项目(2017cstc-jbky-00102);重庆市科研院所绩效激励引导专项项目(cstc2018jxjl0192);重庆市技术创新与应用示范重大主题专项项目(cstc2018jszx-cyzdx0082)~~

摘　　要：镁合金是国际上公认的最有潜力的轻量化材料之一,被誉为“21世纪绿色工程金属”。它的推广应用解决了我国关键装备和重大工程的轻量化问题,缓解了我国日益严峻的环境和能源危机。然而,镁合金强度偏低,尤其是高温强度和抗蠕变性能差,严重阻碍了其发展与应用。因此,常在镁合金中加入不同的合金元素来改善镁合金的微观组织和高温性能,其中价格低廉的碱土金属Sr就是一种提高镁合金高温性能的合金化元素。Sr可以提高镁固溶体的熔点,其在镁合金中扩散缓慢且具有较低的密度,因而在耐热镁合金中得到了广泛的应用。近年来,研究者们主要从Sr元素的成分优化及Sr与其他合金元素的合理搭配方面不断尝试,并取得了丰硕的成果,在适当添加元素Sr及/或其他元素后,耐热镁合金的高温性能得到了改善。目前较常用的镁合金系列有Mg-Al系、Mg-Zn系和Mg-RE系等。对Mg-Al系而言,向镁合金中加入碱土元素Sr,除了起到细晶强化的作用外,还可以在晶界处形成新相,该相具有高的熔点和热稳定性,能阻止高温下镁合金晶粒的长大和晶界的滑移,起到晶界强化的作用,从而明显提高镁合金的高温性能和抗蠕变能力。对Mg-Zn系而言,在铸态Mg-Zn合金中添加Sr元素后,合金的强度均获得一定程度的提高,但是塑性较低。因此研究者越来越关注Sr元素对变形镁合金性能的影响。在变形Mg-Zn合金中添加适量碱土元素Sr,除了起到细晶强化作用外,晶界处会析出Mg-Zn-Sr三元相,其具有更高的热稳定性,能够钉扎晶界,起到晶界强化的作用,提高镁合金的高温力学性能,同时使变形镁合金的塑性也得到提高。对Mg-RE系而言,加入适量的碱土元素Sr,不仅可降低实验成本,而且对合金的组织有很好的细化效果,第二相含量增加并且在晶界处分布更加均匀,使镁合金的高温力学性能得到提高。本文归纳�Magnesium alloys are recognized as one of the most promising lightweight materials in the world.They are known as“green engineering metal in the 21st century”.Its application can solve the lightweight problem of key equipment and major projects and alleviate the increasingly severe environmental and energy crisis.However,the low strength of magnesium alloys,especially the poor performance in high temperature strength and creep deformation resistance,has seriously hindered its development.Therefore,alloying elements could also affect the deformation modes and the final texture either by dissolving in the Mg matrix or forming various precipitates.Among them,low-cost alkaline earth metal Sr is an alloying element which can improve the high temperature properties of magnesium alloys.Sr can improve the melting point of magnesium solid solution,diffuse slowly and has low density in magnesium alloys.It has been widely used in heat-resistant magnesium alloys.In recent years,researchers have been trying to optimize the Sr composition and its reasonable combination with other alloying elements,and have achieved fruitful results.The high temperature properties of heat-resistant magnesium alloys have been improved by adding Sr and/or other elements.At present,the more commonly used magnesium alloys are Mg-Al,Mg-Zn and Mg-RE.For Mg-Al system,adding alkaline earth element Sr can form a new phase at grain boundary besides fine grain strengthening.The phase has high melting point and thermal stability,which can prevent grain growth and grain boundary slip at high temperature and play the role of grain boundary strengthening,thus significantly improving the high temperature properties and creep resistance of magnesium alloys.For Mg-Zn system,the strength of as-cast Mg-Zn alloys increases to a certain extent by adding Sr element,but the plasticity is low.Therefore,researchers pay more and more attention to the effect of Sr on the properties of wrought magnesium alloys.In addition to fine grain strengthening,Mg-Zn-Sr ternary ph

关 键 词：SR 镁合金 耐热 强化机制 晶粒细化 固溶度 晶界强化 

分 类 号：TG146.2[一般工业技术—材料科学与工程]