TiAl-Cr合金中的β₂相

来源期刊：中国有色金属学报1998年第1期

论文作者：郑运荣 汪小平

文章页码：1 - 6

关键词：TiAl基合金 βSUB>2相 Cr的作用

Key words：TiAl base alloys ,β₂ phase,effect of Cr

摘    要：在Ti-(44～48)Al-(3～6)Cr(摩尔分数, %) 的三元合金中，存在B2结构的体心立方有序β₂ 相，其形成与含Cr量有关。β₂相铸态成分可表示为：Ti₅₅Al₃₃Cr₁₂。β₂相是该合金中显微硬度最高的相，其硬度值随合金中Cr 含量增加而提高。β₂相常分布于γ 晶界，起阻碍晶粒长大作用。

Abstract: In the ternary alloys of Ti-(44~48)Al-(3~6)Cr(mole fraction, %), there is an ordered bccβ₂ phase with B2 structure. The formation of this phase is related to the content of Cr. 0.5%(volume fraction) β₂ phase can be precipitated in as-cast Ti-44Al-3Cr alloy. The amount of β₂ phase reaches 6%(volume fraction) after long time soaking from 900 ℃ to 1200 ℃. However, β₂ phase disappears when holding long time above 1250℃. The composition of β₂ phase can be expressed as Ti₅₅Al₃₃Cr₁₂. The microhardness of β₂ phase is the highest among all the phases of the alloy and its microhardness increases with the increase of Cr content in alloys. β₂ phase often distributes at the grain boundaries of γ phase and retards the growth of γ phase grains. The deformation capability of β₂ phase is the weakest in the phases of the alloy and it inhibits the long distance slip, therefore, β₂ phase would make slip dispersive and delay the initiation of cracks.