Di对Mg-10Al合金显微组织与力学性能的影响

研究了Di加入量为1％～3％（质量分数，下同）[Nd—Pr混合稀土金属，w（Nd）：w（Pr）=3：1]的Mg-10Al合金的显微组织和力学性能。通过显微组织分析发现Di加入Mg-10Al合金后，析出了块状的Al2（Nd，Pr）相及杆状的Al11（Nd，Pr）3相，合金组织得到细化。Di的加入使铸态的Mg-10Al合金的力学性能提高，在Di的加入量为2％时，块状的Al2（Nd，Pr）相占主导地位，合金的抗拉强度和伸长率都达到峰值。在Di的加入量达到3％时，杆状的Al11（Nd，Pr），相增加，抗拉强度、尤其是伸长率有所降低。     

Ca对Mg-4Al-1RE合金的组织和力学性能的影响

通过配置6种成分的合金进行的试验发现，铸态AE41合金的显微组织具有典型的树枝晶特征，由α-Mg基体和针状的Al110RE3相组成。AE41合金中加入少量的Ca后，合金的组织得到了细化，同时有新的热稳定相Al2Ca形成。Al2Ca有两种形貌：一种是骨骼状，主要沿晶界分布；另一种呈颗粒状，主要存在于晶粒内部。加入Ca后合金的室温和高温屈服强度以及高温瞬时抗拉强度得到改善，但是同时也降低了合金的塑性。     

旋转式室温磁制冷机用永磁磁路

随着室温磁制冷技术的发展,许多具有巨磁热效应的材料被开发出,但多是在高场强的超导磁体中获得的。为应用磁制冷技术到家用空调和冰箱,除了巨磁热效应的磁致冷材料外,设计出高场强的永磁磁路也尤其重要。针对旋转式室温磁制冷机,采用有限元方法设计并制作了具有较高场强的永磁磁路,在磁路工作气隙为20mm时,工作气隙中心的场强的计算值及实测值均高于1.5T,且计算值与实测值基本相符。     

Zr对Mg-5Sn合金显微组织与力学性能的影响

研究了含Zr0．4％-1．2％的Mg-5Sn合金（质量分数，％，下同）的显微组织和力学性能。显微组织观察表明，Zr元素能够起到明显的晶粒细化作用。扫描电镜EDS分析和XRD分析验证了这一结果。力学性能测试结果表明：随着合金中Zr含量的增加，抗拉强度及延伸率都有提高，延伸率提高更显著，Zr的晶粒细化起了主要作用；而合金的显微硬度基本不变，其原因是在合金中没有明显数量的硬质相出现。     

Microstructures, mechanical properties and compressive creep behaviors of as-cast Mg-5%Sn-（0-1 .0）%Pb alloys

The microstructures, tensile properties and compressive creep behaviors of Mg-5%Sn-(0–1.0)%Pb (mass fraction) alloys were studied. The microstructures of the Mg-Sn-Pb alloys consist of dendritic α-Mg and Mg₂Sn phase. The addition of Pb can refine the size of Mg₂Sn phase and grain size, reduce the amount of Mg₂Sn phase at grain or inter-dendrite boundaries and change the distribution of Mg₂Sn phase. Pb exists in the Mg₂Sn phase or dissolves in α-Mg matrix. The mechanical properties of the tested alloys at room temperature are improved with the addition of Pb. When the Pb content is over 0.5%, the mechanical properties are decreased gradually. The Mg-5%Sn-0.5%Pb shows the best ultimate tensile strength and elongation, 174 MPa and 14.3%, respectively. However, the compressive creep resistance of the Mg-Sn-Pb alloys is much lower than that of the Mg-Sn binary alloy at 175 °C with applied load of 55 MPa, which means that Pb has negative effects on the compressive creep resistance of the as-cast Mg-Sn alloys.     

Effect of Aluminum Coating on Corrosion and Heat Transfer Performance of Magnetic Refrigerant Gadolinium

The surface of gadolinium was covered with a layer of Al film(10-15 μm) by hot-press.Corrosion resistance, thermal conductivity and diffusivity of the composites were studied. As a result,temperature and pressure are the main factors that influence the combination of Gd and Al, and the effect of pressure is especially obvious. When the pressure exceeds 700 MPa, the binding force reaches 9 MPa. After coating, corrosion resistance of the composites is significantly improved, Corrosion rate is significantly reduced and mass loss reduced to one-tenth of pure Gd after 15 days. The current density decreases by an order of magnitude and corrosion potential increases by 0.3 V. The thermal conductivity of the composites is 11.12 W·m~(-1)·K~(-1). Due to good thermal diffusion coefficient of aluminum, the magnetic work piece coated with Al film might show better heat transfer performance.     

Sn合金化对Gd5Si2Ge2磁致冷材料结构和性能的影响

以商业纯Gd为原料,采用非自耗电弧炉氩气保护下熔炼了Gd5Si2Ge2-xSnx(x=0.2,0.5,1)和Gd5Si2-yGe2Sny(y=0.1,0.2,0.5)系列合金,研究Sn合金化对Gd5Si2Ge2晶体结构和磁热性能的影响.粉末XRD结果表明Sn代Ge样品具有正交Gd5Si4型结构;Sn少量代Si(y=0.1,0.2)的样品具有单斜Gd5Si2Ge2型结构;Gd5Si1.5Ge2Sn0.5则为单斜和正交的混合结构.用超导量子磁强计(SQUID)测定了样品的M-T和不同温度的M-H曲线,结果表明Gd5Si2Ge2-xSnx(x=0.2,0.5,1)不具有巨磁热效应;Gd5Si1 9Ge2Sn01合金的最大磁熵变达15.3 J/kg·K(0 T～5 T),具有巨磁热效应.     

Effect of copper ion implantation on corrosion morphology and corrosion behavior of LaFe_（11.6）Si_（1.4） alloy

The morphology analysis and electrochemical method were used to study the corrosion behavior of LaFe11.6Si1.4 alloy of copper ion implantation. X-ray photoelectron spectroscopy (XPS) and atomic emission spectroscopy (AES) research results showed that a 15 nm-thick oxide film was formed on the surface of sample, and the copper content reached the highest value at 60 nm with a normal distribution. Immersion experiments indicated that the corrosion happened in the copper-poor zone firstly and a galvanic connection was formed among different zones on the surface due to the inhomogeneous distribution of copper. Electrochemical experiment results showed that the corrosion was serious when the ion acceleration voltage increased, and the high acceleration could reduce the thermodynamic performance of corrosion of LaFe11.6Si1.4 alloy.     

LaFe11.6Si1.4合金的常温吸放氢行为

利用化学浴法制备了由六棱锥纳米分枝组成的多级分层花型结构的ZnO,并采用溶剂热法在所得ZnO材料表面均匀修饰Au纳米粒子.系统地研究了不同Au纳米粒子修饰量对ZnO气敏性能的影响.结果表明:Au纳米粒子的修饰能显著提高ZnO对丙酮气体的敏感性,当Au修饰量为10％(质量分数),工作温度为270℃时,ZnO表现出最佳灵敏度和选择性,是实际应用中良好的气体敏感候选材料.     

Influence of iron on phase and magnetic property of the LaFe_（11.6）Si_（1.4） compound

The phase relation, microstructure, Curie temperatures, hysteresis, and magnetocaloric effects of LaFex*11.6Si1.4 (x=0.96, 0.98, 1.0, and 1.02) compounds prepared by arc-melting and then annealed at 1423 K (1.5 h)+1523 K (4.5 h) were investigated. The main phase was NaZn13-type phase, the impurity phases included a small amount of α-Fe and LaFeSi phase in four samples. The crystal cell parameters of 1:13 phase increased from 1.1433(5) to 1.1454(4) nm with x increasing from 0.96 to 1.02, respectively. All samples kept the typical first-order magnetic transition. The increase of Fe strengthened IEM behavior, and led to the remarkable enhancement of MCE effect and negative slopes in Arrott plots around TC. The maximum ΔSM (T, H) under a low magnetic field (0-2 T) was 15.3, 16.8, 17.9, and 24.7 J/kg K with increasing of Fe content from x=0.96 to 1.02, respectively.