含Nb的Ti-Al-Si系金属间化合物的热轧组织与性能

Microstructure and Properties of the Ti Al Si Intermetallics with Nb

摘要:

研究了Ｔｉ－２４Ａｌ－１１Ｎｂ－２Ｓｉ和Ｔｉ－２４Ａｌ－１１Ｎｂ－５Ｓｉ金属间化合物合金的热轧组织与性能，结果发现：随着变形量的增加，两种合金第二相Ｔｉ５Ｓｉ３变得细小且趋向于均匀分布。变形量越大，合金的室温四点弯曲程度越大，含Ｔｉ５Ｓｉ３较多的Ｔｉ－２４Ａｌ－１１Ｎｂ－５Ｓｉ合金的弯曲强度较高。两种合金的室温弯曲断口形貌均为准解理形式，两相界面结合较强。高温拉伸试验表明：随变形量的增大，Ｔｉ－２４Ａｌ－１１Ｎｂ－２Ｓｉ合金的拉伸强度和塑性都增加。Ｔｉ－２４Ａｌ－１１Ｎｂ－５Ｓｉ合金由于变形量较大和较高的

关键词:热轧,组织,性能,Ti－Al金属间化合物

Abstract:

The microstructure and properties of hot rolled Ti 24Al 11Nb 2Si and Ti 24Al 11Nb 5Si intermetallic alloys are studied. The results indicate that the precipitate (Ti 5Si 3) in both alloys becomes finer and tends towards a homogeneous distribution with increasing the deformation amount. The larger the deformation amount is, the higher the values of four point bending strength of the alloys at room temperature are. Because larger amout of Ti 5Si 3 exists in Ti 24Al 11Nb 5Si alloy,the bending strength of Ti24Al 11Nb 5Si is higher than that of Ti[ 24Al 11Nb 2Si with increasing the deformation amount. The bending fracture morphologies of both alloys at room temperature show the characteristics of quasicleavage mode, and the bonding strength of phase boundaries is strong. The tensile experiments at high temperature show that the tensile strength and plasticity of Ti 24Al 11Nb 2Si increase with increasing the deformation amount. Because of Ti 24Al 11Nb 5 Si alloy having larger amount of Ti 5Si 3 and larger deformation amount, its tensile strength is much higher than that of Ti 24Al 11Nb 5Si, but its plasticity becomes much lower. The strength of both alloys decreases and their plasticity increases with increasing temperature.

Key words:hot roll, microstructure, property, Ti[ Al intermetallic alloy,