QU Xuanhui HUANC Baiyun LEI Changming CHEN Shiqi Central South University of Technology
,
Changsha
,
China professor
,
Powder Metallurgy Research Institute
,
Central South University of Technology
,
Changsha 410083
,
China
金属学报(英文版)
Synthesis process of a TiAl+TiB_2 composite from the elemental powders was studied by means of differential scanning calorimetry and X-ray diffractometry.TiB_2 particles may form in TiAl matrix at temperature even below 700℃ owing to the exothermic reactions between Ti and Al powders.TiB_2 particles are very thermally stable,and they almost did not change in their relative amount,morphology and size after the synthesized composite was remelted.In addition,the existence of TiB_2 particles has obvious refining effect in the as-cast microstructure of TiAl-base alloys.
关键词:
TiAl alloy
,
null
,
null
,
null
CAO Mingzhou
,
HAN Dong
,
ZHOU Jing
,
LI Dong Institute of Metal Research
,
Academia Sinica
,
Shenyang
,
China Associate Professor
,
Institute of Metal Research
,
Academia Sinica
,
Shenyang 110015
,
China
金属学报(英文版)
The microstructure of Ti-33wt-% Al-(1.6-4.5)wt-% Mn alloys are composed of γ+α_2 phases,but the volume of x_2-phase is a little.Mn alloying decreases the lattice parameters a and c of γ-phase and the c/a ratio becomes nearly to one,because the atomic radius of Mn is less than the atomic radius of Ti or Al.Mn alloying promotes the formation of twins in γ-phase and increases the ability of plastic deformation of TiAl alloys at room tem- perature.
关键词:
TiAl alloy
,
null
,
null
,
null
J.L. Su
,
G.K. Hu
金属学报(英文版)
An analytical micromechanical method is proposed to examine the dependence of plastic deformation on the microstructure for a PST crystal. The sub-domain microstructure of the γ phase and the effect of the α2 phase are taken into account by a proper micromechanical formulation, the dislocation slip and twinning deformation mechanisms are considered in the context of crystal plasticity. The model can well predict the dependence of stress-strain relations on loading angle with respect to the microstructure. The influence of the twinning and lamellar spacing on the deformation behavior and biaxial yield surfaces for PST crystals are also examined.
关键词:
TiAl alloy
,
null
,
null
J. Zhang
,
D. Feng
,
Z.Y. Zhong
金属学报(英文版)
The application advances of TiAl, Ti3Al and Ni3Al base alloys were demonstrated by Central Iron and Steel Research Institute, China. The recent research progresses on improving the reliability of cast TiAl were mainly presented and discussed. The characteristics of the self-oriented lamellar microstructure in cast TiAl were investigated in both as cast and as HIPed states. Based on the mechanical anisotropy of the cast lamellar microstructure, the component specific microstructure design was proposed for a better performance and reliability of cast TiAl.
关键词:
intermetallic
,
null
,
null
Yexin CHEN
,
Xiaojing WAN
,
Weixin XU
材料科学技术（英文）
The interaction of water vapor and oxygen with TiAl-based alloy has been studied with Auger electron spectroscopy and X-ray photoelectron spectroscopy. The results indicate that both surface reactions initiate at a very short exposure (about 6×10(-7) Pa·s) and the oxides Al2O3 and TiO2 form in the surface reactions. In the oxidizing reaction, the water vapor reacts firstly with Al, and then reacts with Ti after certain exposure. The surface reaction of Al with water vapor may be responsible for the environmental embrittlement at room temperature in TiAl-based alloy.
关键词:
Surface reaction
,
null
,
null
李涌泉
,
谢发勤
,
吴向清
,
姚小飞
稀有金属材料与工程
通过1050℃下Si-A1-Y2O3扩散共渗4h的方法在TiAl合金表面制备了Y改性的Si-Al共渗层,采用SEM、EDS和XRD分析共渗层的结构及相组成,并对TiAl合金基体及共渗层的常温(20℃)及高温(600℃)耐磨性进行研究.结果表明:1050℃下共渗4h所制备的Si-Al-Y共渗层具有多层复合结构,由外向内依次为TiSi2外层,(Ti,X)5Si4(X表示元素Nb和Cr)及(Ti,X)5Si3中间层,TiAl2和γ-TiAl内层及富Al的过渡层组成;在常温和600℃高温条件下,Si-Al-Y共渗层的耐磨性均明显优于TiAl合金基体,并且Si-A1-Y共渗层具有良好的耐高温磨损性能,在实验温度条件下其磨损机理无明显变化,均为剥层磨损和磨粒磨损;TiAl合金基体在常温下的磨损机理为犁削磨损和磨粒磨损,在600℃高温下的磨损机理为犁削磨损、氧化磨损和磨粒磨损.
关键词:
TiAl合金
,
Si-Al-Y共渗层
,
渗层结构
,
摩擦磨损
