铸造Mg—RE—Zn—Zr合金的组织和性能

通过熔剂保护顺大气环境下制备了Mg-RE中间合金,并制备了Mg-MM-Zn-Zr,Mg-Nd-Zn-Zr和Mg-Nd-Y-Zr3种稀土镁合,对合金分别进行了热处理,测量了各种状态下试验合金的硬度、抗拉强度及伸长率等力学性能,观察了合金的显微组织。结果发现：含稀土元素Nd,Y的试验合金有良好的热处理强化效果,其硬度和抗拉强度都高出常用的Mg-MM-Zn-Zr合金。从过饱和固溶体中析出的细小弥散的含稀土元素强化相既可提高镁合金的强度,又可以提高镁合金的塑性,使合金由脆性断裂转化为韧性断裂。     

镁—稀土中间合金品位问题初探

在向变形镁合金中添加Mg-Nd、Mg—Y、中间合金时,常常因为Mg—Nd、Mg-Y中间合金中Nd、Y的品位问题,而影响变形镁合金性能的提高或改善,本试验,以Mg—Zn—Zr—Nd、Mg—Zn—Zr—Y系变形镁合金为例,重点研究了Mg—Nd、Mg—Y中间合金中Nd、Y的品位对其性能的影响,结果指出,Mg—Nd、Mg—Y中间合金Nd、Y的品位高于80％时,合金的室温拉伸性能较佳,反之,则合金的室温拉伸性能低劣。     

几种合金元素对镁合金铸造组织与性能的影响

研究了稀土Y、Nd、Gd以及金属Zr对铸态镁合金组织和硬度的影响。结果表明,稀土元素Y能够改善镁合金铸态组织,细化晶粒,金属Zr能在稀土Y细化晶粒的基础上进一步细化合金晶粒;由于细晶强化、固溶强化和第二相强化作用,稀土Y、Nd、Gd和金属Zr能够显著提高合金的硬度。     

稀土元素对镁合金高温力学性能的影响

制备了三种稀土镁合金并对其进行了室温和高温力学性能测试,用X射线、金相显微镜以及扫描电子显微镜对试验合金铸态及挤压态组织进行了分析。结果表明:稀土元素与镁形成的化合物分布在铸态组织晶界并在挤压后沿挤压方向分布,不同的稀土元素对合金高温力学性能有不同的影响。含Nd的合金高温抗拉强度高于含Ce的合金,含 Nd和Y的合金又高于含Nd的合金,其中,含Nd和Y的合金在250℃时抗拉强度为219．6 MPa。高温力学性能的提高主要是由于稀土元素的固溶强化和镁-稀土化合物晶界强化共同作用的结果。     

稀土元素对镁合金高温力学性能的影响

制备了三种稀土镁合金并对其进行了室温和高温力学性能测试，用X射线、金相显微镜以及扫描电子显微镜对试验合金铸态及挤压态组织进行了分析。结果表明：稀土元素与镁形成的化合物分布在铸态组织晶界并在挤压后沿挤压方向分布，不同的稀土元素对合金高温力学性能有不同的影响。含Nd的合金高温抗拉强度高于含Ce的合金．含Nd和Y的合金又高于含Nd的合金，其中，含Nd和Y的合金在250℃时抗拉强度为219．6MPa。高温力学性能的提高主要是由于稀土元素的固溶强化和镁一稀土化合物晶界强化共同作用的结果。     

Y和Gd含量对Mg-Gd-Y-Zn-Zr合金组织与性能的影响

活性稀土元素Y在镁合金熔炼过程中极易形成Y2O3夹杂,降低含Y镁合金铸件的合格率,已成为含Y镁合金推广应用的瓶颈之一。以Mg-Gd-Y-Zn-Zr合金为研究对象,在保持稀土总质量分数不变的前提下,用Gd来部分替代Y,研究了Mg-xGd-(12-x)Y-0.5Zn-0.5Zr(x=9,10,11,12)合金的微观组织与力学性能。结果表明,铸态合金相组成主要为α-Mg基体和(Mg,Zn)_5(Gd,Y)共晶相,经固溶处理后,第二相基本完全固溶,残余第二相粒子为Mg5Gd、Mg3Gd或Mg2Gd相;在225℃下,含Y的镁合金在16h即可达到峰值硬度,而Mg-12Gd-0.5Zn-0.5Zr合金在64h时才达到硬度峰值,且峰值硬度明显低于其他含Y的镁合金;在铸态、固溶态和峰时效态下,Mg-9Gd-3Y-0.5Zn-0.5Zr和Mg-12Gd-0.5Zn-0.5Zr合金的伸长率较低。     

稀土元素和Ti对ZM5镁合金组织和性能的影响

用金相显微镜、X射线衍射仪分析了添加稀土元素Y、Nd和钛中间合金的Mg-8．5Al-0．5Zn（ZM5）合金的组织和相组成,测试了合金的室温力学性能。结果表明,添加稀土元素Y、Nd的ZM5镁合金中出现了新的镁．稀土相MgY、Mg12Nd,而在同时添加稀土元素Y、Nd和钛中间合金的合金中,还出现了新相Ti2Mg3Al18;添加稀土元素Y、Nd的ZM5镁合金在拉伸性能、硬度以及组织都明显优于ZM5镁合金,而同时添加稀土元素和Ti合金的镁合金其性能又显著优于单独添加Y或Nd的合金。     

Mg-5.0Y-3.0Nd-0.5Zr合金铸态组织和力学性能研究

对Mg-5.0Y-3.0Nd-0.5Zr镁合金进行熔铸和不同温度的均匀化退火,测试该合金的室温力学性能。并采用金相显微镜、扫描电镜等观察铸态和均匀化退火态组织。结果表明,添加Nd和Y能使镁合金的铸态组织得到细化,Nd和Y分别以Mg41Nd5和Mg24Y5化合物形式存在,均匀化退火后,试验合金抗拉强度和伸长率得到提高。其中450℃的均匀化退火效果最好,合金的抗拉强度比铸态时的提高了24.5%,伸长率提高了116.7%。     

Mg-RE(Y,Nd,Gd)-Zr合金组织与性能的比较研究

采用金相显微镜、扫描电镜、硬度测试以及电子拉伸等手段,对比研究了Y、Nd和Gd三种稀土元素对镁合金铸态和热处理后显微组织与性能的影响规律。结果表明,三种稀土元素加入合金中,均可以细化组织,提高合金的强度和硬度,特别是经过时效热处理后合金的强度有明显的提高。相同条件下,稀土Nd的晶粒细化作用及强化效果最显著。     

稀土元素Y、Nd对AZ81镁合金组织和高温性能的影响

研究了稀土元素Y、Nd对AZ81镁合金组织和高温力学性能的影响。结果表明，稀土元素Y、Nd的加入明显细化了AZ81镁合金的显微组织，减少了β（Mg17Al12）相的析出。分析认为，稀土元素Y和Nd主要是通过固溶强化、析出强化和细晶强化提高了合金的室温和高温强度，改善了合金的塑性。复合加入2％的Y和Nd，合金的室温强度最高，达282．5MPa，与未加稀土的AZ81相比，约提高了39％。含1％Y的AZ81合金在150℃下的高温强度高达220MPa，与不含稀土的AZ81相比高温强度约提高40％。     

高强Mg-Gd-Y-Zn-Zr合金的微观组织和力学性能

通过金属模铸、热挤压和时效处理(T5)工艺过程制备出高强Mg-7Gd-4Y-1.6Zn-0.5Zr合金,并利用光学显微镜、XRD、SEM及TEM分析研究Mg合金不同状态下的显微组织和力学性能。结果表明:Mg-7Gd-4Y-1.6Zn-0.5Zr合金的铸态组织主要由α-Mg基体和沿晶界分布的片层状第二相Mg12Zn(Gd,Y)组成,经过热挤压变形后,合金晶粒显著细化,时效处理过程中Mg12Zn(Gd,Y)相上析出少量细小的颗粒状Mg3Zn3(Gd,Y)2相。时效态合金的抗拉强度、屈服强度和伸长率分别达到446 MPa、399 MPa和6.1%,其强化方式主要为细晶强化和第二相强化。     

Effects of Y content on microstructures and mechanical properties of as-cast Mg-Zn-Nd alloys

The effects of Y addition amount on the microstructures and mechanical properties of as-cast MgZn-Nd alloy have been investigated by using an optical microscope, a scanning electron microscope, backscattered electronic imaging technique, an X-ray diffractometer, a differential thermal analyzer and a universal testing machine. There are three kinds of ternary phases in the Mg-Zn-Y system alloys, such as I phase(Mg3Zn6Y), W phase(Mg3Zn3Y2) and Z or X phase(Mg12Zn Y). The experimental results in the present study indicate that the Mg-Zn-RE(RE includes Y and Nd) ternary phases change from the I + W phases in turn to unique W, W + Z and unique Z as the Y content increases from 0% to 3%. Simultaneously, their distribution gradually changes from small particle-like form to continuous network form. The grain size first decreases as the Y content increases from 0% to 1% Y, then increases when the Y content exceeds 1% and finally decreases again when the content exceeds 3% due to the variation of growth restriction factor caused by the increased Y element and the change of the ternary phases. The hardness continuously increases because of the increased ternary phase amount. The ultimate tensile strength and elongation first increase within the range of 0-1% Y, also due to the increased ternary phase amount and grain refinement, and then decreases because of the grain coarsening, porosity formation and continuous network distribution of the ternary phases. The grain bonding strength of the W phase-containing alloys is quite strong and the W phase is an ideal strengthening phase if a given amount of it distributes in discontinuous and small-sized form. The alloy with 1% Y only has one ternary phase of W, but has the best combination of mechanical properties. The fracture regimes of these alloys always present a transgranular mode.     

钇含量对Mg-xY-1.5LPC-0.4Zr合金的时效硬化和力学性能的影响(英文)

研究钇含量对Mg-xY-1.5LPC-0.4Zr镁合金的时效硬化、显微组织和力学性能的影响(其中LPC代表富镧混合稀土金属)。当将Y加入Mg-1.5LPC-0.4Zr时,随着Y含量的增加,合金的时效硬化反应相应增强,晶粒尺寸变小,强度增加。当将Y添加到Mg-1.5LPC-0.4Zr合金中时,时效析出相发生改变,由Mg-LPC基合金的稳态Mg12RE相转变为Mg-Y基合金的亚稳态β′相,且随着Y含量的增加,β′相的数量也相应增多。在合金晶界上还发现了稳态立方形的β-Mg24Y5相。对于Mg-Y-LPC-Zr合金,拉伸性能的改善主要归功于均匀、弥散分布的β′相,在晶界上的β-Mg24Y5相对合金的晶界也有明显的强化作用。当Y含量达到6%时,合金的拉伸强度最大,合金在室温和250°C的抗拉强度分别是250 MPa和210 MPa。     

Microstructure and mechanical properties of Mg-6Al magnesium alloy with yttrium and neodymium

The effects of rare earth (RE) elements Y and Nd on the microstructure and mechanical properties of Mg-6Al magnesium alloy were investigated. The results show that a proper level of RE elements can obviously refine the microstructure of Mg-6Al magnesium alloys, reduce the quantity of/β-Mg17Al12 phase and form Al2Y and AI2Nd phases. The combined addition of Y and Nd dramatically enhances the tensile strength of the alloys in the temperature range of 20-175℃. When the content of RE elements is up to 1.8%, the values of tensile strength at room temperature and at 150℃ simultaneously reach their maximum of 253 MPa and 196 MPa, respectively.The main mechanisms of enhancement in the mechanical properties of Mg-6Al alloy with Y and Nd are the grain refining strengthening and the dispersion strengthening.     

Translations: BISITS—British Industrial and Scientific International Translation Service

This paper described the mechanical properties and corrosion behaviour of new designed Mg–Gd–Nd–Zn–Zr alloy processed by equal channel angular pressing (ECAP) at 375°C. An attractive phenomenon was observed. Both strength and ductility of ultrafine grained Mg–Gd–Nd–Zn–Zr alloy were improved after multipass ECAP. The microstructure of the alloys became much finer and more homogeneous with increasing ECAP passes. The yield strength, ultimate tensile strength and elongation of the alloys under eight-pass ECAP process were over 223?MPa, 270?MPa and 36% respectively, showing desirable mechanical properties of equal channel angular pressed Mg–Gd–Nd–Zn–Zr alloy. The equal channel angular pressed alloy displayed a lower corrosion resistance immersed in Hank's solution due to the crystalline defects as well as the galvanic corrosion induced by precipitation of ultrafine β phase particles.     

Mg-7Gd-5Y-1Nd-xZn-0.5Zr(x=0,1,2)挤压态合金微观组织和力学性能

采用扫描电子显微镜、电子背散射衍射、透射电子显微镜、高角度环形暗场-扫描透射,分析了Mg-7Gd-5Y-1Nd-xZn-0.5Zr(x=0,1,2,质量分数,％)挤压态合金微观组织结构和力学性能,旨在探索Zn对于合金性能影响的微观机制.结果表明:在Mg-7Gd-5Y-1Nd-0.5Zr合金中添加Zn元素,不仅形成LPS...     

热处理工艺对高真空压铸Mg–8Gd–3Y–0.4Zr镁合金组织及力学性能的影响

研究T4和T6热处理状态下高真空压铸Mg-8Gd-3Y-0.4Zr（质量分数,%）合金的微观组织、化合物含量、力学性能及断裂行为。铸态Mg-8Gd-3Y-0.4Zr合金微观组织主要由α-Mg和共晶Mg24（Gd,Y）5化合物组成。经固溶处理后,共晶化合物大量溶解于镁基体,合金主要含过饱和α-Mg及方块相。固溶合金中方块相的含量随固溶温度的升高而增大,力学性能也有所提高。根据微观组织结果,确定475℃,2 h为Mg-8Gd-3Y-0.4Zr合金最优固溶方案。合金的最佳屈服强度为222.1 MPa,延伸率可达15.4%。铸态,T4状态下和T6状态下合金的拉伸断裂模式为穿晶准解理断裂。     

均匀化处理和挤压对Mg-Y-RE-Zr合金组织性能的影响

通过调整元素Y的含量,制备了多种Mg-Y-RE-Zr镁合金,对合金不同状态下微观组织和力学性能进行了分析和测试.结果表明,不同合金晶界上的化合物以Mg24Y5,Mg41Nd5,Mg5Gd等为主,随着元素Y含量的增加,晶界上的化合物数量和尺寸增加,晶粒平均尺寸变化较小,保持在50～60μm;经过均匀化处理(535℃×24 h)后,合金中化合物的分布由铸态时连续的岛状分布变为弥散细小的颗粒状分布,Mg5Gd相基本上全部分解并溶入基体中,合金中弥散分布的点状颗粒相主要为Mg24Y5和Mg41Nd5相;经过挤压变形后,合金的组织得到细化,平均晶粒尺寸在20μm左右,合金的抗拉强度、屈服强度和伸长率都有大幅度的提高,其中Mg-5Gd-5Y-3Nd.0.5Zr合金表现出了较好的综合力学性能;在设计的合金中,元素Y的含量(质量分数)应控制在5%以下.     

Effects of minor Y,Zr and Er addition on microstructure and properties of Al-5Cu-0.4Mn alloy

The effect of different contents of Y, Zr and Er on microstructure and properties of Al-5 Cu-0.4 Mn alloy was investigated. T6 heat treatment, OM, SEM and EDS methods were applied to the alloy. The results showed that fluidity and elongation of alloy adding Y, Zr and Er were improved, while with the increase of addition amounts, θ phase increased and grains were trended to grow up gradually. The Al-5 Cu-0.4 Mn alloy presented the maxed style of ductile and brittle fracture. After T6 heat treatment, the precipitation amounts of θ phase decreased dramatically and tensile strength and hardness significantly increased. Especially when addition contents were among 0.1-0.3 wt.%, tensile strength and hardness of heat-treated alloy increased greatly, almost doubled as that of the as-cast state. The tensile strength reached its maximum of 378.43 MPa when the addition amount was 0.3 wt.%. With the further increase of addition amounts, the elongation deteriorated and the proportion of ductile fracture reduced due to the limited dispersion strengthening effect of θ phase and Al_8Cu_4 Er. It demonstrated that addition of 0.1-0.3 wt.% Y, Zr and Er would generate positive effects and influences on Al-5 Cu-0.4 Mn alloy, which is significant for optimizing components and improving properties of Al-5 Cu-0.4 Mn alloy.