分级时效对TB9钛合金芯杆力学性能及组织的影响

Effect of grading aging on mechanical properties and microstructure of TB9 titanium alloy core rod

依托某型号航天用TB9钛合金芯杆,研究了分级时效下TB9合金力学性能及微观组织的变化特点。结果表明,经过480~530℃×6~10 h单级时效处理后,TB9合金抗拉强度、硬度随着时效温度的升高而下降,超过530℃时晶粒有长大趋势。随着保温时间的延长,抗拉强度在480℃时出现增长趋势,最大值达到1698 MPa,530℃时强度呈明显下降趋势,下降近200 MPa。而双级时效处理可以有效消除或抑制合金中ω脆性相生成、均匀组织,同时提高TB9钛合金芯杆拉伸力值和断裂韧性,其综合性能更能满足高性能β合金紧固件的使用要求。

Mechanical properties and microstructure of a certain type of aerospace TB9 titanium alloy core rod after stepped aging were studied.The results show that the tensile strength and hardness of the TB9 alloy decrease with the increase of aging temperature after single-stage aging at 480-530℃for 6-10 h,and the grain size tends to grow when the aging temperature exceeds 530℃.With the increase of aging time,the tensile strength shows an increasing trend at 480℃,and the maximum value reaches 1698 MPa.At 530℃,the strength shows an obvious downward trend,decreasing by nearly 200 MPa.Short time high temperature treatment before single-stage aging can effectively eliminate or inhibit the formation of brittle phase and uniform structure.At the same time,the tensile force and fracture toughness of the TB9 titanium alloy core rod are improved,so that the comprehensive properties can meet the requirements of high propertiesβalloy fasteners.