铸态全片层Ti-46Al-0.5W-0.5Si合金的室温力学性能

Mechanical Properties of As-Cast Full Lamellar Ti-46Al-0.5W-0.5Si Alloy at Room Temperature

摘要:

对具有柱状晶组织的铸态全片层Ti-46Al-0.5W-0.5Si合金纵向和横向试样进行了室温拉伸、室温压缩和三点弯曲试验，并对拉伸试样断口进行了分析。结果表明：铸态全片层Ti-46Al-0.5W-0.5Si合金力学性能存在强烈的各向异性。横向试样的拉伸性能和弯曲性能远远优于纵向试样，但压缩屈服强度低。合金的力学性能取决于加载轴与片层界面的角度，而不是柱状晶轴的方向。横向拉伸试样的拉应力与片层界面平行，α2/γ片层相界面对裂纹的阻碍作用对提高拉伸性能起到了重要作用。纵向压缩试样的压应力与片层界面垂直，使片层间的微裂纹闭合不扩展，压缩屈服强度较横向试样高。

Abstract:

Tensile tests, compression tests and three point bending tests have been conducted on longitudinal and transverse specimens of as-cast full lamellar Ti-46Al-0.5W-0.5Si alloy with columnar grains at room temperature. The fracture surfaces of tensile samples have been investigated to analysis the reason of different mechanical properties. Results show that the alloy exhibits mechanical property anisotropy, the tensile and bending properties of transverse specimens are much better than those of longitudinal specimens, but the compression yield strength is lower. The mechanical properties of the alloy strongly depend on the angle between the loading axis and the lamellar interface, do not depend on the growth direction of columnar grains. When the tensile stress of the transverse specimen is parallel to the lamellar interface, the interface of α2/γ lamellar can effectively block the crack growth, which plays an important role on improving their tensile properties. When the compression stress of the longitudinal specimens is perpendicular to the lamellar interface, the microcracks between lamellae can close up, without any more growing, resulting in obtaining higher compression yield strength.