β型γ-TiAl合金的制备及其反常屈服行为研究

Preparation and anomalous yield behavior of β γ-TiAl alloy

β型γ-TiAl合金具有良好的高温变形能力,为TiAl合金的发展开辟了新的发展方向.采用水冷铜坩埚真空感应熔炼技术制备了β型γ-TiAl合金,即Ti-45Al-9(V,Nb,Y)合金,研究了该合金的铸态组织、相组成及力学性能.结果表明,Ti-45Al-9(V,Nb,Y)合金的铸态组织为近层片组织结构,主要由γ-TiAl相、α2-Ti3Al相及β(B2)相组成.室温条件下,该合金的屈服强度为393MPa,700℃时合金的屈服强度为562MPa,当测试温度升高到800℃时,合金的屈服强度为420MPa.该合金表现出了明显的反常屈服行为.

β γ-TiAl owned excellent deformability at high temperature and it was regarded as a new material which exhibited potential for using in different fields in the future. In this paper,Ti-45Al-9（V,Nb,Y） alloy,a new β γ-TiA alloy,was prepared successfully by Induction Skull Melting （ISM） technology in water-cooled copper crucible,and its microstructure,phase constitution and mechanical properties were investigated. The results showed that Ti-45Al-9（V,Nb,Y） alloy,with nearly lamellar structure,was composed of γ-TiAl,α2-Ti3Al andβ（B2） phases,and had obvious anomalous tensile behavior. The yield strength of Ti-45Al-9（V,Nb,Y） alloy was 393MPa at room temperature,562MPa at 700℃ and 420MPa at 800℃,respectively.