摘要
采用元素粉末经热压烧结法制备了新型Ti-43.5Al-4Nb-1Mo-0.3B合金,研究了热处理工艺对合金组织中β相转变行为及其力学性能的影响。结果表明,粉末冶金态Ti Al合金中β相呈条带状,与γ相形成块状组织。热处理能显著改善材料的组织均匀性,使B2/γ块状组织逐渐转变成α2/γ层片组织,β相转变行为特征为吸收Ti、Al元素,排出Nb元素。温度是热处理过程中组织均匀化的主控因素,在共析温度Te附近热处理时（1100-1160℃/24 h）,B2相逐渐溶解但不能完全消除,而在α相转变温度Tα以上短时热处理和稳定化低温热处理后,如1400℃/2 h/FC＋850℃/6 h/AC,B2/γ块状组织可完全消除,且组织粗化不严重。初始态B2相纳米硬度为6.69 GPa,弹性模量为175.4 GPa,热处理导致其纳米硬度和弹性模量逐渐降低。
A new type Ti-43. 5Al-4Nb-1Mo-0. 3B alloy was prepared by hot-pressing sintering method using element powders. The effects of the heat treatment on the transition behavior and characteristics of β phase in the Ti Al alloy were investigated. The results demonstrate that the β phase in PM Ti Al alloy is bornded,which is integrated with γ phase to form the bulk microstructure. Heat treatment can significantly improve the uniformity of the microstructure,which makes the B2 / γ bulk microstructure gradually transform to fine α_ γlamellar structure. During the heat treatment,the β phase absorbs Ti and Al and discharges Nb. The heat treatment temperature is the dominant factor affecting the microstructure evolution. During the heat treatment near the eutectoid transformation temperature,1100-1160 ℃ /24 h,the initial β phase is partly dissolved,while after the short time heat treatment above Tαtemperature and subsequent stabilization heat treatment,i. e. 1400 ℃ /24 h / AC ＋ 850 ℃ /6 h / AC,the initial β phase is completely eliminated without obviously grain coarsening. The nano-hardness and elastic modulus of the initial β phase is 6. 69 GPa and 175. 4 GPa,respectively. Heat treatment at 1100 ℃ to 1160 ℃ for 24 h decreases the nano-hardness and elastic modulus of the β phase.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2015年第12期19-25,共7页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51175059)
中央高校基本科研业务费专项资金(DUT14YQ105)
新世纪优秀人才支持计划资助(NCET-10-0278)
