陈敏
,
刘源
,
李言祥
,
陈祥
金属学报
本文研究了不同Cr含量的AlTiFeNiCuCrx多主元高熵合金的微观组织和力学性能特点。结果表明，Cr含量的增加使合金的凝固模式从亚共晶向过共晶凝固转移，铸态组织由一先析出枝晶相和枝晶间的菊花状共晶组织组成。合金仅由简单的面心立方结构(富Cr相)和体心立方结构(贫Cr相)两相组成。Cr含量的增加对合金硬度的提高较小。该合金为室温脆性材料，但在1073K高温时具有很好的塑性变形能力和较高的强度，当xCr=1-1.5左右时，合金具有最优的压缩强度和塑性组合。
关键词:
多主元合金
,
High-entropy alloy
,
Microstructure
,
Properties
Z.Z. Yang
,
W. Tian
,
Q.R. Ma
,
null
,
null
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
Since the development of offshore oil and gas, the increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipeline were depended on importing because of the strict requirements of comprehensive properties such as anti-corrosion, resistance to pressure and so on. In order to research and develop domestic steel pipe used for submarine pipeline, the Longitudinal-seam Submerged Arc Welded (LSAW) pipes were made of steel plates cut from the levelled steel rolls by both JCOE and UOE forming process. And the mechanical properties of the pipe base metal and weld metal were tested, the results were in accord with the corresponding pipe specification API SPEC 5L or DNV-OS-F101, which showed the domestic LSAW pipes could be used to the submarine oil and gas pipeline.
关键词:
Mechanical Properties
,
Properties
,
Offshore
,
oil
,
and
,
g
Zhi-Hong Jia
,
Hui-Lan Huang
,
Xue-Li Wang
,
Yuan Xing
,
Qing Liu
金属学报(英文版)
doi:10.1007/s40195-016-0379-0
Lots of the available literatures on hafnium in aluminum alloys are reviewed. The new binary Al-Hf phase diagram is simply assessed. Two ternary phase diagrams including Al-Hf-Zr and Al-Hf-Sc are accounted for, with emphasis on the aluminum rich part of the diagrams. The relationship between different structure Al3Hf and several different formation mechanisms including the probable phase transformation mechanisms is described. The continuous Al3Hf phase particles can serve as a grain refiner in the Al melt and a precipitate for controlling the grain structure of the alloy and a strengthening precipitate. A series of effects of Fe, Si, Zr, Sc and Li addition on the behavior of Al3Hf and Al alloys are given. Moreover, the effects of Hf on the microstructure and properties of Al alloys, such as hardness and creep, are reviewed. Finally, some views of Hf-containing Al alloys are summarized.
关键词:
Al-Hf
,
Phase
,
diagram
,
Al3Hf
,
precipitate
,
Microstructure
,
Properties
Wenhui LIU
,
Yangai LIU
,
Shoumei XIONG
,
Baicheng LIU
,
Y.Matsumoto
,
M.Murakami
材料科学技术（英）
Casting pressure conditions have great influences on the casting defects, such as gas porosity, shrinkage porosity and gas holes. A Mg cylinder head cover die casting was used to experimentally study the influences of casting pressure, the loading time and the piston position of pressure intensification on the variation of pressure and the quality of casting. The results show that casting pressure, the loading time and the piston position of pressure intensification have great influences on the pressure variations in the mold, the quality and performance of casting. The external quality, the density and the tensile strength of casting were improved with the increase of casting pressure and the piston position of pressure intensification and the decrease of the loading time of pressure intensification.
关键词:
Magnesium alloy
,
null
,
null
,
null
,
null
Min ZHAO
材料科学技术（英）
TiB2P/Al composite was successfully fabricated by squeeze casting technology. Its mechanical and tribological properties were evaluated. The elimination of Ti-Al intermetallic compound was confirmed by X-ray diffraction (XRD) studies. At 45% volume fraction, the bending strength at ambient temperature was 934 MPa. And the fracture modes included ductile failure of Al matrix and brittle fracture of TiB2 particles. In dry sliding wear mode, severe plastic deformation and adhesive wear were found on the worn surfaces of the SiCP/Al composite. But no obvious characteristics of adhesion or abrasion wear were observed on that of the TiB2P/Al composites. At the steady stage, the friction coefficient of the SiC2P/Al composite was about 0.6. While that of TiB 2P/Al composite was only about 0.16~0.17.
关键词:
TiB2
,
null
,
null
,
null
Jinfeng XU
,
Qiuya ZHAI
,
Sen YUAN
材料科学技术（英）
Energy-storage welding connection characteristics of rapidly solidified AZ91D Mg alloy ribbons with 40~70 μm thickness are investigated using a microtype energy-storage welding machine. The microstructure and performance of the connection joints are analyzed and studied. The research results indicate that energy-storage welding is able to realize the spot welding connection of AZ9ID Mg alloy ribbons. The welding nugget consists of developed α-Mg equiaxed grains with the sizes of 1.2~2.7 μm and intergranular distributed β-Mg17Al12 compounds. The thickness of bond zone is about 4 μm and the solidification microstructure is characterized by the fine equiaxed grains with the sizes of 0.8~1.2 μm, and grain boundary has become coarsening. The columnar crystal in HAZ also becomes slightly coarsening and the grain boundary has broadened, however, there is no obvious change in its primitive morphology and crystallographic direction. When welding energy is about 2.0 J, the welding joints with higher shear strength and smaller electrical resistivity are obtained.
关键词:
AZ91D
,
null
,
null
,
null
,
null
Qijie ZHAI
,
Li FU
,
Huaying ZHAI
材料科学技术（英）
Effect of Nb on microstructure and mechanical properties of chilled cast iron at room and elevated temperatures is studied in this research. The results demonstrate that the cast structure and mechanical properties of chilled cast iron at room and elevated temperatures are improved with the addition of trace amount of Nb. However, if Nb was added too much, the cast structure and mechanical properties of chilled cast iron would deteriorate. The suitable content of Nb in chilled cast iron is about 0.05% (mass fraction). Except the dissolution in the matrix of cast iron the excessive Nb will form Nb-rich phases in three morphologies. Those are lumpy NbC, complicated strip-like phase and compound with pearlite structure.
关键词:
Nb
,
null
,
null
,
null
Wen CHEN
,
Manzhu KE
,
Qing XU
,
Quanyao ZHU
,
Liqiang MAI
,
Li LI
材料科学技术（英）
In this article, the vanadium pentoxide sols are synthesized by two different routes (melted and quenched in oxygen atmosphere or in air). The structure and properties of the vanadium pentoxide xerogel films are characterized by XRD, ESR, cyclic voltammograms curves and UV-visible transmittance analysis. The results show that the sample prepared in oxygen has poorer crystallization, lower content of V4+ ions and higher Li+ insertion capacity compared with that prepared in air.
关键词:
Preparation atmosphere
,
null
,
null
,
null
王力
,
张保红
,
林冰涛
,
唐亮亮
,
邝用庚
宇航材料工艺
对自发汗冷却材料的种类及特点进行了简介,综述了自发汗冷却材料的几种主要制备方法及其优缺点,详细阐述了自发汗冷却材料的研究现状、影响因素及其应用,并对其发展方向进行了讨论.
关键词:
自发汗冷却材料
,
工艺
,
性能
,
应用
叶宏
,
王宾
,
龙刚
,
邓代玉
表面技术
doi:10.3969/j.issn.1001-3660.2010.01.006
为提高镁合金表面的耐蚀性,采用热喷涂技术在AZ31镁合金表面制备铝涂层,并利用脉冲钨极氩弧表面熔覆的方法进行表面重熔,获得富铝的合金化层,分析了合金化层的组织结构和性能.研究结果表明:在AZ31镁合金表面的铝合金化层中存在典型的树枝晶结构,含有金属间化合物Mg_2Al_3,Mg_(17)Al_(12)以及α-Mg和Al固溶体.显微硬度测试表明,铝合金化可使AZ31镁合金表面硬度由HV50左右提高到HV200左右.极化曲线测试表明,合金化层提高了镁合金表面的耐蚀性.
关键词:
镁合金
,
脉冲钨极氩弧
,
Al合金化
,
性能
