Effect of Cu addition on microstructure and properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy

To improve the strength,hardness and heat resistance of Mg-Zn based alloys,the effects of Cu addition on the as-cast microstructure and mechanical properties of Mg-10Zn-5Al-0.1Sb high zinc magnesium alloy were investigated by means of Brinell hardness measurement,scanning electron microscopy (SEM),energy dispersive spectroscopy (EDS),XRD and tensile tests at room and elevated temperatures.The results show that the microstructure of as-cast Mg-10Zn-5Al-0.1Sb alloy is composed of α-Mg,t-Mg32(Al,Zn)49,φ-Al2Mg5Zn2 and Mg3Sb2 phases.The morphologies of these phases in the Cu-containing alloys change from semi-continuous long strip to black herringbone as well as particle-like shapes with increasing Cu content.When the addition of Cu is over 1.0wt.%,the formation of a new thermally-stable Mg2Cu phase can be observed.The Brinell hardness,room temperature and elevated temperature strengths firstly increase and then decrease as the Cu content increases.Among the Cu-containing alloys,the alloy with the addition of 2.0wt.% Cu exhibits the optimum mechanical properties.Its hardness and strengths at room and elevated temperatures are 79.35 HB,190MPa and 160MPa,which are increased by 9.65%,21.1% and 14.3%,respectively compared with those of the Cu-free one.After T6 heat treatment,the strengths at room and elevated temperatures are improved by 20% and 10%,respectively compared with those of the as-cast alloy.This research results provide a new way for strengthening of magnesium alloys at room and elevated temperatures,and a method of producing thermally-stable Mg-10Zn-5Al based high zinc magnesium alloys.     

Effects of Sb Addition on Microstructural Evolution and Mechanical Properties of Mg–9Al–5Sn Alloy

The Mg–9Al–5Sn-xSb(x=0.0,0.3,0.6,1.0,1.5 wt%) alloys were prepared by a simple alloying process followed by hot extrusion with an extrusion ratio of 28.2. The effects of Sb additions on the microstructure and mechanical properties of the Mg–9 Al–5 Sn alloys were investigated by optical microscopy, X-ray diffraction, transmission electron microscopy, scanning electron microscopy equipped with an energy-dispersive X-ray spectrometer. The results indicated that the phases α-Mg matrix, Mg_2_Sn, Mg_3Sb_2 and Mg_17 Al_12 exist in the as-cast Sb-containing alloys. Sb addition results in the precipitation of Mg_3Sb_2. The dendritic size of these alloys decreases with the addition of Sb. Both their ultimate tensile strength and yield strength of extruded alloys increase, and their elongation decreases gradually with increasing the content of Sb. The better mechanical properties of the as-extruded alloys were achieved due to the refined grains and the formation of dispersive second phases Mg_3Sb_2.     

Sr和Sb变质AZ61-0.7Si合金的铸态组织和力学性能

Mg2Si相的变质和细化被认为是改善含Si镁合金力学性能的关键因素之一.研究了Sr和Sb变质AZ61-0.7Si镁合金的铸态组织和力学性能.研究结果表明:添加0.4%(质量分数)Sb对AZ61-0.7Si镁合金中的汉字状Mg2Si相有一定细化作用,但没有明显变质效果.相反,添加微量Sr对AZ61-0.7Si合金中的汉字状Mg2Si相有明显变质和细化作用.在AZ61-0.7Si合金中添加0.03%～0.09%Sr(质量分数)后,合金中的Mg2Si相从粗大汉字状形貌变为细小的颗粒状和/或多边形状.相应地,合金的抗拉性能和蠕变性能得到显著提高.     

Effect of Sb on the grain refinement and tensile properties of Mg-10Zn-5AI alloys

In the present research, the Sb-alloying method was adopted, and the grain refinement and tensile. properties of as-cast Mg-10Zn-5AI alloys with varying Sb addition were investigated. The results showed that with the Sb addition, a new phase (Mg3Sb2) of high melting point forms in the alloy beside the α-Mg matrix, τ-Mg32(AI, Zn)49 phase and φ-Al2Mg6Zn2 phase. With an appropriate amount of Sb addition, the morphologies of the secondary phases and the matrix are changed and the grains are refined. When Sb addition is 0.6wt.%, both ambient and high temperature tensile strengths of the alloy reach their maximum. The hardness of the alloy increases with the increasing of Sb addition. With proper addition of Sb, the tensile failure mode of the alloy changes from cleavage fracture to quasi-cleavage fracture, showing good enhancement effect.     

Sb变质对Mg_2Si/AM60镁基复合材料组织及性能的影响

研究了Sb对Mg2Si增强相及基体组织的细化效果及机理。结果表明,Sb加入可生成Mg3Sb2,Mg3Sb2能够作为Mg2Si的异质核心,使得Mg2Si由汉字状变成颗粒状,并弥散地分布。同时,基体组织也得到细化,改善了合金的力学性能。加入0.8%的Sb后,合金的抗拉强度提高了12.2%。     

耐热铸造镁合金的研究应用进展

介绍了耐热镁合金的蠕变特点及其强化方法。分析了Mg—AI系、Mg—Zn来和Mg—RE系合金耐热性能改善的组织结构因素。探讨了现有耐热镁合金存在的问题和新型耐热镁合金研究开发的方向。     

On the precipitation of magnesium silicide in irradiated aluminium–magnesium alloys

Thermal neutron irradiation of aluminium or its alloys causes the production of silicon by transmutation. In aluminium–magnesium alloys, the transmutation-produced silicon reacts with magnesium and forms small precipitates. The precipitation in irradiated Al–Mg alloys is similar to the early stage of aging in thermally treated Al–Mg–Si alloys. This study evidences the simultaneous generation of two crystallographically different precipitate types. On the basis of electron diffraction patterns, unit cell parameters are derived and compared with structures found in thermally aged alloys. One of the two precipitate types has an Mg₂Si composition, while the other is an Al–Si–Mg intermetallic compound with high aluminium and silicon but low magnesium content. The formation of magnesium poor precipitates is important since it indicates that the threshold neutron fluence for grain boundary precipitation of silicon may be much higher than estimated in the past.     

Bi合金化在耐热镁合金中的应用

介绍了合金元素Bi的特性(在镁中的溶解度高,可实现沉淀强化)及其在镁合金中的作用(细化组织,改善高温性能),综述了Bi合金化在耐热镁合金中的应用研究进展,在此基础上,指出了含Bi耐热镁合金存在的问题和发展的方向.     

New engine coolant for corrosion protection of magnesium alloys

The global trend toward decreasing of atmospheric pollution, by saving fuel consumption in vehicles, has led to extensive interest of using lightweight metals such as magnesium alloys, in engine and cooling system components. The modern coolant is not intended to prevent corrosion of magnesium alloy in the engine cooling systems. We have developed a new coolant that aims to protect Mg alloy parts together with all other commonly used metals. Several inhibitor formulations were tested, according to glassware test (ASTM D1384) and heat transfer conditions (ASTM D4340). Mg alloys EZ33 and WE43 were added to the standard sets of metals and the corrosivity of different types of formulations was determined by weight loss measurements. The new anticorrosive coolant showed high performance in all tested metals including magnesium alloys and it satisfied the requirements (ASTM D3306). Cyclic potentiodynamic polarization curves have been used to study electrochemical corrosion behavior of the magnesium alloys EZ33 and WE43 in aqueous solution containing the inhibitors and ethylene glycol (33 vol%‐EG prepared with corrosive water according to ASTM D1384) and compared to a reference coolant with no inhibitor. It was found that a passive film was created upon the Mg alloys, which exhibited high corrosion resistance against pitting.     

锑对AZ91D镁合金微观组织的影响

研究了锑对AZ91D镁合金微观组织的影响。在AZ91D镁合金熔炼过程中加入三氧化二锑引入锑元素,用光学显微镜对加锑前后合金显微组织及其变化情况进行研究,发现锑的加入可使AZ91D镁合金的组织发生明显变化,β-Mg17Al12脆性相由连续网状分布逐渐变为离散状。同时利用扫描电镜、能谱仪和透射电镜分析了锑在合金中的存在形式。结果表明,锑在AZ91D镁合金中主要以两种形式存在:固溶在α-Mg、β相中;形成新相Mg3Sb2。锑在镁合金中生成的新相Mg3Sb2既作为异质形核核心细化组织,又会聚集在固液界面前沿抑制晶体的长大,从而对镁合金起到细化晶粒的作用。     

Mg3Sb2含量对Al-Mg3Sb2复相涂层耐磨性的影响

目的研究Mg_3Sb_2含量对Al-Mg_3Sb_2复相涂层的组织、硬度和摩擦学性能的影响,对比分析AZ31B镁合金基体、纯Al涂层和添加不同含量的Mg_3Sb_2之后涂层性能的差异。方法通过火焰喷涂技术在AZ31B镁合金表面制备了Al-Mg_3Sb_2复相涂层。利用扫描电镜(SEM)观察了涂层的截面形貌,利用X射线衍射仪(XRD)分析了涂层的物相组成。通过显微硬度计测试了AZ31B和涂层的硬度,通过摩擦磨损试验仪测试了AZ31B和涂层的摩擦学性能,并通过超景深三维显微镜测试了试样的磨痕宽度、深度及磨损体积。结果经火焰喷涂后可得到组织致密的复相涂层,涂层中的物相主要为Mg_3Sb_2和Al。涂层的平均硬度随Mg_3Sb_2含量的增加而增加,最高可达334.2HV0.025,是AZ31B的4.14倍。摩擦磨损试验中,涂层的摩擦系数随着Mg_3Sb_2含量的增加而减小,但都大于AZ31B的摩擦系数;涂层的磨损率随着Mg_3Sb_2含量的增加而减小,60%Mg_3Sb_2和80%Mg_3Sb_2涂层的磨损率小于AZ31B的磨损率,其他涂层的磨损率大于AZ31B的磨损率,80%Mg_3Sb_2涂层的耐磨性最好,比AZ31B下降了63.26%。随着Mg_3Sb_2含量的增加,Al-Mg_3Sb_2复相涂层的磨痕表面犁沟逐渐变浅并消失。结论 Mg_3Sb_2的加入可以提高涂层的硬度,随着其含量的增加,涂层的耐磨性逐渐提高。     

医用可降解镁合金抗菌性、溶血以及生物相容性的研究进展

镁及镁合金因其密度低、弹性模量与硬组织匹配、可降解吸收以及具有优异的生物相容性等优点已成为可降解生物材料领域的研究热点。但镁合金体内降解速率过快且降解时产生析氢反应并引发局部pH环境升高,这会影响周围组织的生长,甚至会发生溶血、溶骨现象,这严重限制其在临床上应用。采用添加适当合金元素以及镁合金表面改性被认为是减缓镁合金腐蚀速率以期达到其降解行为可控的有效方法。综述了可降解镁合金抗菌性和溶血性能的研究状况,系统阐述了近5年来可降解镁合金生物相容性的最新进展,展望了医用可降解镁合金未来的研究方向和挑战。     

医用稀土镁合金微观组织特征及力学行为研究进展

近年来,镁合金作为生物医用金属材料受到了广泛关注,但其较差的力学强度极易导致植入物在服役周期内崩塌断裂,严重危及患者生命安全。稀土微复合金化作为当下提高可降解镁合金力学性能的有效措施,在消除镁合金杂质元素、净化熔体的同时,还可以起到促进动态再结晶、形成长周期堆垛有序相等作用。因此,本文从稀土镁合金微观结构转变及其与力学性能的基本关联出发,综述了近年来医用稀土镁合金组织特征及力学性能的研究进展,深入发掘了稀土元素、第二相及镁合金力学性能之间的本质关联,详细阐述了连续动态再结晶对稀土镁合金的强韧化机理,全面叙述了稀土元素诱导长周期堆垛有序结构对镁合金力学性能的影响规律。最后,本文对医用稀土镁合金未来的发展方向进行了展望。     

耐热镁合金及其开发思路

简述了耐热镁合金的特点和概况,介绍了舍金化耐热镁合金、镁基复合材料和快速凝固镁合金3大领域,重点分析了开发新型耐热镁合金的思路、方法与需要注意的问题,并提出了一些建议,为进一步拓宽镁合金在汽车、航天航空、3C产品等领域的应用提供理论依据。     

合金元素对镁合金耐热性能的优化作用及机理

论述了耐热镁合金的研究现状.介绍了锂、硅、钙、锡、铋、锑、银、钍、稀土以及其中的钕、锆元素对镁合金性能尤其是耐热性能的作用及影响机理,总结了提高镁合金高温性能的途径.最后指出发展耐热镁合金的主要方向.     

合金元素对Mg-Al-Si系镁合金中Mg2Si相形貌影响的研究进展

合金化和微合金化作为变质Mg-A1-Si系镁合金中汉字状Mg2Si相的一种工艺手段,目前已引起国内外的广泛关注和高度重视,并对此开展了大量的研究。本文综述了合金元素变质Mg-Al-Si系耐热镁合金中汉字状Mg2Si相的研究进展,尤其是Al、Si、Sb、Ca、P、RE和Sr等合金元素对汉字状Mg2Si相形貌的影响及其变质机理,指出了目前还存在的问题,并对今后的发展进行了展望。     

Electrochemical Performance Estimation of Anodized AZ31B Magnesium Alloy as Function of Change in the Current Density

The anodized AZ31B magnesium alloys were synthesized via electrodeposition processes. The aim of this work was to determine the electrochemical behavior of magnesium alloys by using anodized alloys as a protective coating. The anodized alloys were characterized by x-ray diffraction, exhibiting the crystallography orientation for Mg and MgO phases. The x-ray photoelectron spectroscopy was used to determine the chemical composition of anodized magnesium alloys. By using electrochemical impedance spectroscopy and Tafel curves, it was possible to estimate the electrochemical behavior of anodized AZ31B magnesium alloys in Hank’s balanced salt solution (HBSS). Scanning electron microscopy was performed to analyze chemical changes and morphological surface changes on anodized Mg alloys due to the reaction in HBSS/anodized magnesium surface interface. Electrochemical behavior in HBSS indicates that the coatings may be a promising material for biomedical industry.     

稀土Y+AZ91D镁合金的微观组织及耐蚀性研究

通过盐雾腐蚀试验,研究了稀土Y对AZ91D镁合金耐腐蚀性能的影响。用光学显微镜(OM)观察组织结构,应用XRD对其进行物相分析,采用静态失重法计算其腐蚀速率,比较含Y和不含Y的AZ91D镁合金的组织和耐腐蚀性能。结果表明,Y+AZ91D镁合金在NaCl溶液中具有优异的耐蚀性,并且随Y含量的增加,Mg17Al12相增多,针状组织Al4MgY也增多,细化了合金的微观组织,耐腐蚀性能也进一步得到提高。     

锑含量对Mg-6Al-6Si合金组织性能的影响

Mg-Al-Si系合金（AS系列）在凝固过程中容易形成粗大Mg2Si相,严重影响材料的性能。通过添加Sb使Mg2Si尺寸和形状得到改善,以提高材料的性能。结果表明,加入Sb后合金的铸态组织得到明显改变,随Sb加入量的增加初晶Mg2Si逐渐消失,树枝状Mg2Si变得更加细小、弥散,当Sb含量为1.0%时,初晶Mg2Si已完全消失,此时合金的抗拉强度达到最大值。