曹名洲
,
韩东
,
张涛
,
李东
金属学报
用气体雾化方法制备了Ti-34Al-2Mn合金的微晶粉末,粉末典型粒度为27μm。X射线衍射结果表明,快冷态的粉末主要由α_2相和少量γ相组成。金相组织显示出等轴块状晶粒和树枝状结晶两种形态。经900℃,2h真空退火后,大部分α_2相转变成γ相,使原来的组织更加细化。
关键词:
快速凝固
,
TiAl alloy
,
microstructure
李夕金
,
张大蔚
,
薛文斌
材料热处理学报
在TiAl合金表面以等离子液相沉积方法制备了Al2O,膜.扫描电镜观察膜为多孔结构,沉积膜的内部孔的直径约30 μm,表面孔的直径约有10 μm;多孔结构的膜硬度约为1200 HV;沉积膜的主要相成分是γ-Al2O3及少量的α-Al2O3;显微划痕实验结果表明膜层与基体之间有较好的结合力,划痕超声信号出现在15 N压力附近;利用SEM及EDS能谱分析膜层破裂机制,膜层的开裂主要是由于基体在压力作用下的变形导致.
关键词:
Al2O3膜
,
等离子液相沉积
,
性能
,
TiAl合金
D Song
,
G.Y Zeng and X. Y Sun (Material Testing Centre
,
Northeastern University
,
Shenyang 110006
,
China Manuscript received 24 August 1995
,
in revised form 30 March 1996)
金属学报(英文版)
In the present paper, the microstructures of the two-phase alloy specimens of Ti-48AlMn-Nb, deformed at room temperature, 700℃and 900℃,have been investigated by using an EM400T transmission electron microscope. For specimens deformed at room temperature it is observed that (1/2) [011] superdislocation, normal (1/2) [110] dislocations, stacking fault band and a few twins etc. formed mainly in r-phase and a (1/2) [011] superdislocation preferentially decomposes into two partial dislocations with an antiphase boundary between them, which makes the dislocation difficult to move. The normal (1/2) [110] dislocations move with a long dragging tail behind them and have a low mobility In addition, the existence of a few twins implies a low mobility of (1/6) <112> twin dislocations, which leads to low plasticity of the allow. For samples deformed above 700℃,(1/2) [110] dislocations are in majority in the r-phase and exhibit short and bending dislocation segments without dragging tails,which may have resulted from an increased mobility of (1/2) [110] dislocations due to thermal activation. Meanwhile, (1/2) [011]superdislocation disappears, the mobility of (1/6)<112> dislocations is greatly increased, and thus a lot of twins are produced in r-phase. These make the plasticity of the alloy notably enhanced. The laminated structures in the alloy may be transformed into stacking fault bands during deformation at room temperature and the deformation above 700℃leads to the generation of a great quantity of twins.
关键词:
: dislocation
,
null
,
null
,
null
