稀土在镁合金中作用的研究现状

稀土元素在镁合金中具有阻燃、净化熔体等作用,能有效改善合金的铸造性能;可细化显微组织、形成准晶相、抑制形变织构,提高镁合金的室温及高温强度和塑韧性等力学性能;并改变镁合金表面腐蚀层结构、控制阴极相数量和分布以及影响电化学过程,从而改善镁合金的耐腐蚀性能。总结了利用稀土元素改善镁合金组织性能的研究现状,并对稀土镁合金的发展前景进行了展望。     

稀土在镁合金中作用的研究现状

稀土元素在镁合金中具有阻燃、净化熔体等作用，能有效改善合金的铸造性能；可细化显微组织、形成准晶相、抑制形变织构，提高镁合金的室温及高温强度和塑韧性等力学性能；并改变镁合金表面腐蚀层结构、控制阴极相数量和分布以及影响电化学过程，从而改善镁合金的耐腐蚀性能。总结了利用稀土元素改善镁合金组织性能的研究现状，并对稀土镁合金的发...     

稀土元素对镁合金力学行为影响的研究现状

系统论述了不同稀土元素的结构特性,基于镁合金的强化机制,并结合当前稀土镁合金的研究现状,展示了稀土元素的添加对镁合金在强度、塑性及抗蠕变性能等方面带来的变化,尤其是对镁合金塑性的影响.其中,区别于传统的强化机制,对添加稀土元素后出现的LPSO结构相对镁合金性能的影响也进行了重点讨论,进一步对镁合金中的稀土元素合金化后的改性作用及前景进行了探讨和展望.     

稀土元素对镁合金力学行为影响的研究现状（英文）

系统论述了不同稀土元素的结构特性,基于镁合金的强化机制,并结合当前稀土镁合金的研究现状,展示了稀土元素的添加对镁合金在强度、塑性及抗蠕变性能等方面带来的变化,尤其是对镁合金塑性的影响。其中,区别于传统的强化机制,对添加稀土元素后出现的LPSO结构相对镁合金性能的影响也进行了重点讨论,进一步对镁合金中的稀土元素合金化后的改性作用及前景进行了探讨和展望。     

稀土变形镁合金的研究和开发

论述了国内外稀土变形镁合金的研究和开发现状,分析了在变形镁合金中添加稀土元素所起的作用以及稀土对合金组织、性能及变形加工能力所产生的影响,总结了稀土变形镁合金中准晶相的形成、作用及研究特点,讨论了稀土变形镁舍金研究和开发中存在的问题和困难,指出稀土变形镁合金是镁合金开发应用中的一个重要发展方向.     

镁合金稀土元素合金化研究进展

本文叙述了国内外镁合金稀土元素合金化的研究进展;讨论了稀土元素对镁合金熔体、组织和性能以及耐腐蚀性的影响;分析了镁稀土合金研究存在的问题;指出镁稀土合金是镁合金研究的重要发展方向。     

稀土在镁及镁合金中的作用

综述了稀土元素在镁合金溶液中去氧化夹杂、除氢和与熔剂的相互作用,以及稀土元素对镁及镁合金的组织、性能、起燃温度、耐蚀性等方面的影响.阐述了RE在镁合金显微组织中细化晶粒、强化晶粒和晶界、提高合金力学性能的机理,以及与氧等元素反应在镁合金表面生成MgO、Al2O3、RE2O3、Mg17Al12组成的致密保护膜和由于Ce、Y、Le等元素的加入形成稀土转化膜对镁合金起燃温度、耐蚀性的作用.并对含稀土镁合金进行了评价与展望.     

稀土镁合金抗高温蠕变性能的研究进展

稀土元素在镁合金中能够细化晶粒尺寸,可以利用其固溶强化和第二相强化机制提高合金力学性能,改善镁合金的抗高温蠕变能力。介绍了镁合金的蠕变机理,以及稀土Y元素、Gd元素、Sc元素和Ce元素对镁合金组织和蠕变性能的影响,综述了目前国内外开发的Mg-Y、Mg-Gd、Mg-Sc、Mg-Ce等一系列稀土镁合金的研发现状,对稀土镁合金的发展现状给予意见,并对稀土镁合金的发展前景进行展望。     

稀土在铝、镁合金中的应用

稀土元素作为微量元素加入铝、镁合金中,可以净化合金熔体,细化、变质微观组织,减少夹杂.随着稀土元素加入量的增加,可以显著提高铝、镁合金的综合性能特别是高温力学性能.综述了含稀土铝合金和稀土镁合金的研究、发展和应用现状,着重介绍了稀土对铝镁合金冶炼、工艺和合金化的影响.展望了稀土铝、镁合金的发展前景.     

稀土耐热镁合金的开发与应用

介绍了稀土元素的特性和耐热镁合金合金体系设计思路.重点阐述了稀土耐热镁合金的开发与应用现状以及稀土在镁合金体系中的影响机理,指出在Mg-Al系的基础上开发出适合汽车用稀土耐热镁合金是今后重点发展方向.     

Mg-Al系耐热镁合金中的合金元素及其作用

合金化或微合金化作为改善合金性能或设计新型合金的重要手段之一,目前已普遍应用于Mg-A1系耐热镁合金的研究开发中.综述了Mg-Al系耐热镁合金中合金元素Al、Zn、Mn、Sb、Bi、Sn、Si、RE、Ca和Sr的作用行为,重点分析了Al和Zn 2种主体元素对Mg-Al系耐热镁合金组织和性能的影响,讨论了合金元素使用中存在的问题和今后的发展方向.     

镁合金化阻燃的研究进展

介绍了添加各种合金元素(包括Ca、Be、Zn、Ba、RE以及复合添加)对镁合金的阻燃和抗氧化性能的影响规律,展望了阻燃镁合金的发展趋势和潜在应用领域,即通过多元微合金化设计提高镁合金的阻燃性能,并兼顾其塑性变形能力,发展高速交通工具用阻燃变形镬合金挤压型材.     

RE对Mg-8Zn-4Al-0.3Mn镁合金阻尼性能的影响

研究了 RE对Mg-8Zn-4Al-0.3Mn镁合金阻尼性能的影响.研究表明,加入RE后降低了合金低温下的阻尼性能,但明显提高了其在高温下(≥120℃)的阻尼性能.高温下,加入1.0%RE的合金表现出了最高的阻尼性能.由于高温下合金中相界面的软化及粘性滑动,四种合金在高温下均存在一个温度内耗峰,只是出现的温度不同.RE的加入推迟了温度内耗峰出现的温度.分析认为,加入RE后合金的阻尼机制主要是位错机制和界面机制.可动位错密度越高,晶粒越细,晶界和相界越多,阻尼性能越好.     

Structure,mechanical and corrosion properties of extruded Mg-Nd-Zn,Mg-Y-Zn and Mg-Y-Nd alloys

Rare earth elements are known to improve both mechanical and corrosion properties. However, it highly depends on the final microstructure conditions of prepared material. During extrusion, intermetallic phases may be redistributed, partially dissolved or on the contrary, precipitated. The knowledge of the impact of extrusion on the individual alloys is therefore essential for their application. In this work, three magnesium alloys (Mg-4Y-3RE, Mg-2Y-1Zn, Mg-3Nd-0.5Zn) were prepared by an extrusion process. Microstructure, mechanical and corrosion properties were compared with extruded pure Mg. The advantages and disadvantages of individual alloys are discussed. Based on the obtained results, the Mg-4Y-3RE alloy seems to exert the best mechanical and corrosion properties. Other materials were characterised with anisotropy of mechanical properties and much higher corrosion rate.     

合金元素对镁合金耐腐蚀性能影响的研究进展

添加合金元素即合金化是改善镁合金性质、性能的有效途径。总结了基础合金元素(Al、Zn、Mn、Zr等)和微量合金元素(Ce、La、Sc、Er、Nd、Y、Sm、Ho、Gd及混合稀土等稀土元素和Ca、Sr等碱土金属元素以及Pb、Sn、Sb、Si、Hg、Ga等)对合金化镁合金耐腐蚀性能的影响,评述了失重法、电化学方法等合金化镁合金耐腐蚀性能的主要研究方法,指出了当前镁合金合金化及耐腐蚀性能研究中存在的问题和发展方向。     

Explaining texture weakening and improved formability in magnesium rare earth alloys

Wrought magnesium alloys are rarely used due to their poor formability which is caused by strong textures created during processing. Addition of rare earth (RE) elements including Y, Ce, La, Gd and Nd weakens these strong basal textures and significantly improves formability. Developing a mechanistic understanding of this effect is critical in leading alloy design towards a new class of highly formable magnesium alloys. This fall in texture intensity occurs during recrystallisation and only requires very low solute RE additions, 0·01 at.-% in the magnesium–Ce case. These additions retard dynamic recrystallisation and increase non-basal slip; however, a full understanding of the RE effect has yet to be obtained, with a variety of mechanisms proposed. Recent research in these areas is critically reviewed.     

The Effect of Different Sterilization Methods on the Mechanical Strength of Magnesium Based Implant Materials

The research on the development and characterization of potential magnesium biomaterials is a steadily expanding. Commonly, implants present a high risk of infection for their recipients. For this reason, a pre‐operative sterilizing process is required. Due to the temperatures and media which are used while sterilizing, effects may occur which cause a change in the mechanical strength of certain magnesium alloys. Four commonly used sterilization methods (autoclave sterilization, dry heat sterilization, gamma sterilization and ethylene oxide sterilization) were investigated to gain information about their influences on the quasi‐static mechanical behavior of LAE442 (Mg 90 m.%, Li 4 m.%, Al 4 m.%, RE 2 m.%), MgCa0.8 (Mg 99.2 m.%, Ca 0.8 m.%) magnesium alloys as well as pure magnesium. The mechanical properties exhibited by the sterilized and non‐sterilized alloys refer to susceptibilities of the mechanical strengths to the investigated sterilization methods. Such susceptibilities appear to be dependent on the combination of alloy and method of sterilization. However, the maximum changes in mechanical strength appear in the range of ±10%. Within this study, ETO sterilization caused the least changes in the mechanical strength of the alloys and appears to be the best performer.     

Effects of neodymium rich rare earth elements on microstructure and mechanical properties of as cast AZ31 magnesium alloy

Abstract

The effects of neodymium rich rare earth elements [RE(Nd)] on microstructure and mechanical properties of as cast AZ31 magnesium alloy were investigated. The microstructures of as cast AZ31–xRE(Nd) alloys display a dendrite configuration, and the secondary dendrite spacing of the α-Mg phase was decreased with the increasing Nd content. The addition of RE(Nd) resulted in the formation of Al₂Nd and Mg₁₂Nd phases. Mechanical properties were improved significantly due to grain refinement and precipitation of intermetallic phases. When the amount of RE is 1·0 wt-%,The as cast AZ31 alloy reached its maximum tensile strength of 249 MPa at room temperature, yield strength of 169 MPa and elongation of 9·0%.