Ti-43Al-4Nb-1Mo-0.2B合金多道次热轧后冷却速率对其组织演化及性能的影响  

Effect of the Cooling Rate on the Microstructure Evolution and Properties of Ti-43Al-4Nb-1Mo-0.2B Alloy After Multiple Pass Hot Rolling

作　　者：卫贝贝 马彪 陈晓飞 张翔[1] 唐斌[1,2] WEI Beibei;MA Biao;CHEN Xiaofei;ZHANG Xiang;TANG Bin(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China;Innovation Center NPU Chongqing,Chongqing 401135,China)

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072 [2]西北工业大学重庆科创中心,重庆401135

出　　处：《铸造技术》2025年第4期307-315,共9页Foundry Technology

基　　金：国家重点研发计划(2021YFB3702604);西北工业大学博士学位论文创新基金(CX2023045)。

摘　　要：在多道次热包套轧制变形后,冷却速率对TiAl合金板材的显微组织演变及其宏观力学性能具有显著的调控作用。以Ti-43Al-4Nb-1Mo-0.2B(原子分数,%,简称TNM合金)合金为研究对象,通过炉冷及空冷两种冷却方式调控轧后冷却速率,系统研究了不同冷速下TNM合金板材显微组织形貌、相变过程及再结晶行为,进而对合金室温力学性能进行测试并阐明其变形机制。研究结果表明,缓冷促进了α_(2)/γ片层团内部及边界处α_(2)→βo相变,同时有利于片层团周围等轴γ再结晶形核以及长大。而快冷促进了α_(2)→γ相变,α_(2)/γ片层间距由缓冷条件下的140 nm减小至60 nm。此外,快冷条件下形成非均匀厚度的γ板条以及片层团周围少量的γ再结晶使得TNM合金板材的室温强塑性同时提高,抗拉强度达到1 140 MPa,断裂应变超过1%。Cooling rate significantly influences the microstructural evolution and mechanical properties of TiAl sheets following multipass hot-pack rolling.In this study,Ti-43Al-4Nb-1Mo-0.2B(at.%,TNM)sheets were prepared through furnace-cooling and air-cooling methods after rolling.The microstructural morphology,phase transformation,and recrystallization behavior of TNM sheets were systematically investigated at different cooling rates.Furthermore,the mechanical properties of the alloy at room temperature were evaluated,and the underlying deformation mechanisms were clarified.The results indicate that slow cooling facilitates theα_(2)→βo phase transition both within and at the boundaries ofα_(2)/γlamellar colonies while also promoting the nucleation and growth of equiaxedγrecrystallized grains surrounding these colonies.However,compared with slow cooling,rapid cooling promotes theα_(2)→γphase transition,resulting in a decrease in theα_(2)/γinterlamellar spacing from 140 nm to 60 nm.In addition,the strength and plasticity of the TNM sheets are simultaneously enhanced because theγlaths have heterogeneous thicknesses and fewγrecrystallized grains surround theα_(2)/γlamellar colonies under rapid cooling conditions,achieving a tensile strength of 1140 MPa and an engineering strain exceeding 1%.

关 键 词：TiAl板材 冷却速率 组织演化 拉伸性能 

分 类 号：TG146[一般工业技术—材料科学与工程]