The influence of mischmetal and tin on the microstructure and mechanical properties of Mg-6Zn-5Al-based alloys

The influence of the addition of mischmetal (MM) and tin (Sn) (total content of mischmetal and tin = 4 wt.%) on the microstructure, aging behavior and mechanical properties of Mg-6Zn-5Al-based alloys has been investigated. The microstructure of the as-cast alloys consists of alpha-Mg. Mg-32(Al,Zn)(49), Al2Mg5Zn2, Mg2Sn and Al2MMZn2 phases, and the morphology of these intermetallic phases varies with different MM and Sri additions.

Microstructure and Strengthening Mechanism of Die-Cast Mg-Gd Based Alloys

Mg-8Gd-2Y-Nd-0.3Zn (wt%) alloy was prepared by the high pressure die-cast technique. The microstructure, mechanical properties in the temperature range from room temperature to 573 K, and strengthening mechanism were investigated. It was confirmed that the Mg-Gd-based alloy with high Gd content exhibited outstanding die-cast character. The die-cast alloy was mainly composed of small cellular equiaxed dendrites and the matrix. The long lamellar-shaped stacking compound of Mg3X (X: Gd, Y, Nd, and Zn) and polygon-shaped.

Micro structures, tensile properties and corrosion behavior of die-cast Mg-4Al-based alloys containing La and/or Ce

In order to study the properties of Mg-Al-RE (AE) series alloys, the Mg-4Al-4RE-0.4Mn (RE= La, Ce/La mischmetal or Ce) alloys were developed. Their microstructures, tensile properties and corrosion behavior have been investigated. The results show that the phase compositions of Mg-4Al-4La-0.4Mn alloy consist of alpha-Mg and Al11La3 phases. While two binary Al-RE (RE = Ce/La) phases, Al11RE3 and Al2RE, are formed in Mg-4Al-4Ce/La-0.4Mn alloy, and Al11Ce3 and Al2Ce are formed in Mg-4Al-4Ce-0.4Mn alloy.

Microstructure and mechanical properties of high performance Mg-Gd based alloys

The Mg-12Gd-4Y-2Nd-0.3Zn-0.6Zr (wt.%) alloy was prepared by casting technology, and the structure, age hardening behavior and mechanical properties of the alloy have been investigated. The results demonstrated that the alloy was composed of alpha-Mg matrix, a lot of dispersed Mg24RE5 (RE = Gd/Y/Nd) and Mg5RE precipitates in the as-cast and the T6 state alloys. The alloy exhibited remarkable age hardening response and excellent mechanical properties from room temperature (RT) to 300 degrees C by optimum solid solution and aging conditions. The ultimate tensile strength.

Explosive consolidation of amorphous cobalt-based alloys

This paper addresses the explosive consolidation of amorphous cobalt-based alloys. Using the experimental setup introduced in the present paper, specimens with high compact density, excellent magnetic properties and great wearability have been made. In comparison with permalloy and ferrite, the present specimens exhibit superior magnetic properties. Therefore, the compact is deemed as being a promising material for magnetic recording heads.

Magnesium-Based 3D Metal-Organic Framework Exhibiting Hydrogen-Sorption Hysteresis

A new magnesium metal-organic framework (MOF) based on an asymmetrical ligand, biphenyl-3,4',5-tricarboxylate (H3PT) has been synthesized and structurally characterized. MOF Mg-3(BPT)(2)(H2O)(4) (1) consists of 10 hexagonal nanotube-like channels and exhibits pronounced hydrogen-sorption hysteresis at medium pressure.

Effect of Zn concentration on the microstructures and mechanical properties of extruded Mg-7Y-4Gd-0.4Zr alloys

Microstructures and mechanical properties of the Mg-7Y-4Gd-xZn-0.4Zr (x = 0.5, 1.5, 3, and 5 wt.%) alloys in the as-cast, as-extruded, and peak-aged conditions have been investigated by using optical microscopy, scanning electron microscope, X-ray diffraction, and transmission electron microscopy. It is found that the peak-aged Mg-7Y-4Gd-1.5Zn-0.4Zr alloys have the highest strength after aging at 220 A degrees C. The highest ultimate tensile strength and yield tensile strength are 418 and 320 MPa, respectively. The addition of 1.5 wt.% Zn to the based alloys results in a greater aging effect and better mechanical properties at both room and elevated temperatures. The improved mechanical properties are mainly ascribed to both a fine beta' phase and a long periodic stacking-ordered structure, which coexist together in the peak-aged alloys.

Structure and mechanical properties of Mg-Zn-RE system alloys

The lightest density of Mg has stimulated renewed interest in Mg based alloys for applications in the automotive, aerospace and communications industries. However, Mg in the pure form has relatively low strength, limited ductility and is susceptible to corrosion. Great efforts have been made to improve the mechanical properties of Mg alloys. Alloying Mg with other elements is one of the most important methods. An important class of Mg alloys is the Mg-Zn-RE system (RE = rare earth elements). In recent few decades, a series of new Mg-Zn-RE system alloys have been obtained, and detailed the structure and mechanical properties of the alloys. In this paper, the structure and mechanical properties of the Mg-Zn-RE alloys have been summarized. It showed that these alloys have high strength and they are prospected to be widely used in the future.

耐热Mg-Gd基合金的研究和应用

本研究从二元Mg-Gd体系出发，研究了添加不同稀土元素对Mg-Gd基合金的组织、时效行为和力学性能的影响。优化出多种力学性能优异、加工性能良好和耐热性突出的新型Mg-Gd-RE-Zn-Zr系合金。在探讨Mg-Gd基合金强化机理的同时，提出了强化模型，并进行了定量分析。 在Mg-Gd二元体系中，通过对不同Gd含量的合金组织，时效行为和力学性能的研究，发现Gd不仅可以细化晶粒，还可以细化枝晶。合金中Gd的含量大于8 wt.%开始表现出时效硬化现象，Gd含量超过12wt.％时效硬化效果显著。在二元体系研究结果的基础上，选用Mg-8Gd基合金，研究了不同轻稀土元素LRE(La, Ce和Nd)和重稀土元素HRE (Y, Dy, Ho 和Er)对合金组织和性能的影响。结果表明，轻稀土中Nd的作用效果最好，其次为Ce和La。重稀土中Y和Dy的作用效果较好，其次为Ho和Er。将轻、重稀土综合考虑，在Mg-8Gd-3RE(Nd+Y)-Zr合金中，变化Nd和Y的添加量，发现Nd和Y的添加量分别为1 和2或2和1时，能够明显改善合金的综合力学性能。 研究了Mg-8Gd-2Y-1Nd-0.3Zn和Mg-8Gd-1Dy-0.3Zn压铸合金的组织和性能。研究表明，两种合金的铸造性能好，而且具有优异的抗拉性能和蠕变性能，可以满足在250℃~275℃环境下使用。进一步研究了挤压变形Mg-8Gd-2Y-1Nd-0.3Zn合金。合金成形性能好，抗拉强度和伸长率明显提高，而且改善了合金的高温抗蠕变性能，比压铸合金提高了近一个数量级。 发明了一种新型的分步固溶处理方法——振荡热处理方法，这种方法比传统的T6热处理方法更加有效，振荡热处理的主要作用是改变了凝固过程中析出相的尺寸和分布。 研究了Mg-Gd基合金凝固过程中的相析出和相转变。在合金的凝固过程中，容易生成块状的化学组成为Mg5RE（fcc结构）的共晶相；加入Zn后，凝固中容易出现片状的Mg3RE（14H型）沉淀；时效强化的主要原因是在过饱和固溶体时效过程中析出针状的50 nm~100 nm的Mg15RE3相，它与基体具有半共格的位相关系，能够有效阻止位错滑移。但随着时效时间的延长，针状析出相长大，共格关系被破坏，导致强化作用降低。而对于压铸和挤压变形合金，合金析出相的种类不变，主要的不同是挤压变形合金析出化合物的分布更加均匀，尺寸更小。 开发了高强度耐热Mg-12Gd-4Y-2Nd-0.4Zn-0.6Zr合金，这种合金经过热处理后，力学性能优良，热稳定性突出。在300 ℃的抗拉强度约为300 MPa，400 ℃的抗拉强度在100 MPa以上。本合金流动性能良好，适合于砂型铸造，在具有高温、高强度要求的镁合金制品方面极具潜力。 从金属材料强化原理出发，建立了Mg-Gd基合金的强化模型，并进行了定量分析。结果表明，析出强化是Mg-Gd基合金的主要强化方式，但实际试验值和理论值略有偏差，分析认为主要是由于β'相体积分数的变化区间较宽，且合金制备过程中不可避免地产生一些微观缺陷所致。 采用新型合金制备出了一些工业用品部件，探索了该类合金在机械、汽车和高技术等工业领域中的潜在应用

Effect of substitution of chromium for nickel on structure and electrochemical characteristic of Ti0.26Zr0.07V0.24Mn0.1Ni0.33 multi-phase hydrogen storage alloy

Ti-Zr-V-Mn-Ni-based multi-component alloys demonstrate high discharge capacity in KOH electrolyte. However, the drastic decrease in their discharge capacities makes them unsuitable for use as negative electrode material in the Ni/MH battery. In present work, Ni is partially replaced by Cr in the Ti-Zr-V-Mn-Ni-based alloys to improve their cycle life. The effects of Cr substitution on microstructures and the electrochemical characteristics of the alloys are investigated. It is found that Cr substitution is very effective to improve the cyclic durability of the alloys although the discharge capacity decreases with changing x from 0.05 to 0.20. Some kinetic performances have been also investigated using electrochemical impedance spectroscopy (EIS) and potentiostatic discharge technique.

Extended application of edge-to-edge matching model to HCP/HCP (alpha-Mg/MgZn2) system in magnesium alloys

In the present work, the edge-to-edge matching model has been introduced to predict the orientation relationships (OR) between the MgZn2 phase which has hexagonal close packed (HCP) structure and the HCP a-Mg matrix. Based on the crystal structures and lattice parameters only, the model has predicted the two most preferred ORs and they are: (1) [1 1 2 3](alpha-Mg) vertical bar vertical bar]1 1 2 3](alpha-Mg), (0 0 0 1)(alpha-Mg) 0.27 degrees from (0 0 0 1)(MgZn2), (1 0 1 1)(alpha-Mg) 26.18 degrees from (1 1 2 2)(MgZn2), (2) [1 0 1 0](alpha-Mg),vertical bar vertical bar[1 1 2 0](MgZn2), (0 0 0 1)(alpha-Mg) vertical bar vertical bar(0 0 0 1)(MgZn2), (1 0 1 1)(alpha-Mg) 3.28 degrees from ( 1 1 2 2)(MgZn2). Four experimental ORs have been reported in the alpha-Mg/MgZn2 system, and the most frequently reported one is ideally the OR (2). The other three experimental ORs are near versions of the OR (2). The habit plane of the OR (2) has been predicted and it agrees well with the experimental results.

Effect of Carbon Addition on Microstructure and Mechanical Properties of Ti-Based Bulk Metallic Glass Forming Alloys

A kind of novel Ti-based composites was developed by introducing different amounts of carbon element to the Ti-50 Cu-23 Ni-20 Sn-7 bulk metallic glass forming alloys. The thermal stability and microstructural evolution of the composites were investigated. Room temperature compression tests reveal that the composite samples with 1% and 3% (mass fraction) carbon additions have higher fracture strength and obvious plastic strain of 2 195 MPa, 3.1% and 1 913 MPa, 1.3% respectively, compared with those of the corresponding carbon-free Ti-50 Ni-20 Cu-23 Sn-7 alloys. The deformation mechanisms of the composites with improved mechanical properties were also discussed.