Ti90及其优化合金的组织与力学性能研究

Microstructure and Mechanical Properties of Ti90 and Optimized Alloy

摘要:

Ti90合金是我国自主研发的一种新型近α型钛合金,具有高比强度、高韧性、耐蚀和加工性能好等优点。本课题组前期对Ti90合金进行了成分优化,得到一种名义成分为Ti-5. 5Al-4. 0Zr-1. 0Sn-0. 3Mo-1. 0Nb的优化合金。利用X射线衍射仪、金相显微镜、电子探针显微分析仪、电子万能试验机和电化学工作站等检测仪器,对Ti90及其优化合金的组织与力学性能进行对比分析。结果表明,优化合金组织为带有网篮特征的魏氏组织,原始β晶界和α集束清晰可见,有少量残留β相分布于α片层之间。与Ti90合金相比,优化合金的压缩屈服强度与断裂韧性得到了显著的提高,极限应变量有所增加,电化学腐蚀性能较好。

Abstract:

Ti90 alloy is a new near-α titanium alloy with the properties of high strength,high toughness,good resistance to corrosion,outstanding process ability and so on,independently developed in China. Based on Ti90 alloy,an optimized alloy with the nominal composition of Ti-5. 5 Al-4. 0 Zr-1. 0 Sn-0. 3 Mo-1. 0 Nb was obtained by our research group. The microstructures and mechanical properties of optimized alloy and Ti90 alloy were investigated by means of X-ray diffraction( XRD),optical microscope,electron probe micro analyzer( EPMA),electronic universal testing machine and electrochemical workstation. The optimized alloy exhibits typical widmannstatten structures with basketweave characteristic; the prior-β grain boundary and α cluster can be clearly observed; the retained β phase can also be found between lamellar α phase. Compared with Ti90 alloy,optimized alloy has apparently improved compressive yield strength,fracture toughness and a better electrochemical corrosion resistance,with its ultimate strain enhanced slightly.