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以真空自耗电弧熔炼技术熔炼名义成分为Ti-47Al-2Nb-2Cr-0.4(W,Mo)(摩尔百分数)的TiAl合金铸锭,并以该熔炼铸锭进行无包套的近等温锻造实验,研究该TiAl合金铸锭的高温可锻性、显微组织及拉伸性能。结果表明:在无包套的近等温锻造工艺中,该熔炼铸锭显示出较好的高温可锻性,经涂覆玻璃粉浆保护,铸锭在经过60%锻造变形后其锻饼表面无明显裂纹。TiAl合金的铸造组织由细小、均匀的层片状晶团(α2+γ)和少量存在于片层团界的等轴γ晶粒构成;经近等温锻造后,锻饼组织则主要由平均晶粒尺寸为20μm的等轴γ晶粒和一些破碎的片层组织构成,在一些难变形区域,依然存在弯曲变形的片层组织。室温拉伸性能检测表明,由于晶粒细化效应,锻饼的平均抗拉强度由铸锭的433MPa提高到573MPa。
The TiAl alloy ingot with the nominal composition of Ti-47Al-2Nb-2Cr-0.4 (W, Mo) (mol%) was melted by vacuum consumable arc melting technique and the uncoated near-isothermal forging Experimental study of the TiAl alloy ingot high temperature malleability, microstructure and tensile properties. The results show that the smelting ingot shows good high temperature malleability in the process of uncoated isothermal forging. The surface of the ingot after 60% forging deformation is protected by coated glass paste Clearly cracked. The microstructure of TiAl alloy is composed of fine and uniform lamellae (α2 + γ) and a small amount of equiaxed γ grains existing in the lamella of briquette. After being isothermally forged, the structure of the crumb is mainly composed of the average grain The grain size is 20μm equiaxed γ grains and some broken lamellar structure, in some difficult deformation areas, there are still bending deformation of the lamellar structure. Tensile tests at room temperature showed that the average tensile strength of the forged cake increased from 433 MPa to 573 MPa due to the grain refining effect.