粉末冶金TNM合金的热挤压显微组织与力学性能研究  

Microstructure and Mechanical Properties of Extruded TNM Alloy Prepared via Powder Metallurgy

作　　者：王慧琴 孙鹏[1] 潘翔宇 陈晓飞 王怡蕾 李金山[1] 唐斌[1] WANG Huiqin;SUN Peng;PAN Xiangyu;CHEN Xiaofei;WANG Yilei;LI Jinshan;TANG Bin(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China)

机构地区：[1]西北工业大学凝固技术全国重点实验室,陕西西安710072

出　　处：《铸造技术》2025年第3期215-223,共9页Foundry Technology

基　　金：国家重点研发计划(2021YFB3702605)。

摘　　要：针对航空发动机对轻质、高强、高温结构材料的需求,采用TNM预合金粉末经热等静压烧结后得到致密的TiAl合金坯料,对该坯料在1300℃条件下通过热挤压工艺(挤压比λ=5)制备了TNM合金挤压棒材,对热等静压态和挤压态TNM合金的显微组织演变和力学性能进行分析。结果发现,挤压后TNM合金由近γ组织转变为双态组织。其中,挤压态合金中细小的片层团主要来源于挤压后冷却过程中的α→α_(2)+γ相变。此外,γ相由细小的等轴晶粒和被拉长的晶粒组成,前者由再结晶形成,而后者则为不完全再结晶晶粒。通过GOS图对挤压态合金的再结晶程度进行统计,发现挤压后合金的再结晶体积分数为87.8%,可以观察到挤压后α_(2)相形成了{0001}基面丝织构。最后,对热等静压态和挤压态TNM合金的室温拉伸性能进行测试,结果表明挤压后合金的强度和塑性分别提高了56.43%和250%。On the basis of the demand for lightweight and high-strength high-temperature structural materials for aeroengines,a dense TiAl alloy ingot was prepared by hot isostatic pressing of TNM prealloyed powder.The TNM alloy bar was subsequently fabricated via hot extrusion at 1300℃with an extrusion ratio of 5,and the microstructure and mechanical properties of the hot isostatic pressed(HIPed)and extruded TNM alloys were subsequently analysed.The results show that the microstructure of the TNM alloy transforms from a near-γmicrostructure into a duplex microstructure after extrusion.Among them,the fine lamellar colonies mainly originate from theα→α_(2)+γphase transformation during the cooling process after extrusion.Theγphase comprises two distinct morphologies:fine equiaxed and elongated grains.The former is formed through recrystallization,whereas the latter are incomplete recrystallized grains.A statistical analysis of recrystallization of the extruded alloy is conducted via GOS mapping,revealing that the recrystallized volume fraction of the alloy is 87.8%.Furthermore,the{0001}basal texture of theα_(2)phase was found after extrusion.Finally,the tensile properties of the HIPed and extruded TNM alloys at room temperature were tested.The strength and plasticity of the alloys increase by 56.43%and 250%,respectively,after extrusion.

关 键 词：TIAL合金 热挤压 组织演变 力学性能 

分 类 号：TG146.2[一般工业技术—材料科学与工程] TG113[金属学及工艺—金属材料] TG115[金属学及工艺—金属学]