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通过挤压比为14(变形量90%)、名义成分为Ti-46Al-2.5V-1.0Cr-0.3Ni%(原子分数)的TiAl合金开坯组织进行热处理,获得了细小全层片组织。组织观察表明,全层片组织的层片团尺寸平均为85μm,层片团尺寸范围在70～100μm内;采用透射电镜测量层片间距的平均为89 nm;合金中B2相呈条状或块状在层片团界断续的析出。力学性能测试结果表明,合金具有较好的室温塑性和断裂韧性,其室温强度平均达803 MPa,延伸率平均为2.2%;断裂韧性值较高、平均达31.5 MPa.m1/2。断口观察和分析表明,细小的层片团尺寸和层片间距、以及锯齿形层片界面增加了裂纹扩展路径;未见B2相对合金室温塑韧性的不利影响。
The microstructure of the TiAl alloy with the nominal composition of Ti-46Al-2.5V-1.0Cr-0.3Ni% (atomic fraction) was heat-treated by the extrusion ratio of 14 (90% of deformation) to obtain a fine full-layer structure. Tissue observations showed that the average size of the lamellae in the whole lamellar structure was 85μm and the lamellar size ranged from 70μm to 100μm. The average lamella spacing was 89 nm by transmission electron microscopy. In the lamellar community intermittent precipitation. The results of mechanical properties test show that the alloy has good room-temperature plasticity and fracture toughness. The average room temperature strength is 803 MPa and the average elongation is 2.2%. The fracture toughness value is high, with an average of 31.5 MPa.m1 / 2. Fracture observation and analysis showed that the small lamellar size and lamellar spacing, as well as the crack propagation path increased at the zigzag lamellar interface; no adverse effects on room-temperature plastic ductility of B2 relative alloys were found.