固溶时间对Ti-22Al-24Nb合金力学性能及断裂行为的影响

Effect of solution time on mechanical properties and fracture behavior of Ti-22Al-24Nb alloy

对Ti-22Al-24Nb合金进行不同时间的固溶处理,采用拉伸试验和平面应变断裂韧性测试,结合光学显微镜和扫描电镜观察合金微观组织及断口形貌,分析固溶时间对Ti-22Al-24Nb合金力学性能及断裂行为的影响。结果表明：经不同固溶时间处理后,合金断裂形式是解理断裂;随固溶时间的增加,合金断口的韧窝数量先增加后减少,强度先降低再升高,塑性和断裂韧性呈先升高再降低的趋势;当固溶120 min时,Ti-22Al-24Nb合金具有最佳的强韧性匹配,KIC达最大值为51.6 MPa·m^1/2,其抗拉强度为950 MPa,屈服强度为915 MPa,伸长率和截面收缩率分别为15.69%和42.28%。

Microstructure and fracture morphology of Ti-22 Al-24 Nb alloy after solution treatment at 1000 ℃ for different time were studied by tensile test,plane strain fracture toughness test,optical microscope and scanning electron microscopy,and the effect of solution time on mechanical properties and fracture behavior of the Ti-22 Al-24 Nb alloy was analyzed. The results show that the fracture mode of the alloy is cleavage fracture after solution at 1000 ℃ for different time. With the increasing of solution time,the number of dimples on the fracture surface of the alloy first increases then decreases,the strength first decreases then increases,and the ductility and fracture toughness first increase then decrease. When the solution time is 120 min,the Ti-22 Al-24 Nb alloy has the best match of strength and toughness,and the maximum value of KIC is 51. 6 MPa·m^1/2,the tensile strength is 950 MPa,the yield strength is 915 MPa,and the elongation and cross section shrinkage are 15. 69% and 42. 28%,respectively.