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通过等温锻造对Ti60/Ti-22Al-25Nb双合金焊件焊接界面进行了强化,研究了应变速率对等温锻造过程中母材和焊接接头组织的影响,并对锻后和热处理后的双合金件进行了室温力学性能测试。结果表明,经等温锻造后,焊缝原始粗大枝晶被破碎并发生动态再结晶形成细小等轴晶粒。焊接时形成的偏析、孔洞、夹杂等被压实或者压合,使组织变得更加紧密。焊缝中针状脆性O相和马氏体α’相在高温下发生分解,分别形成α_2相和α+β相,而分解后形成的α/α_2相被变形破碎并发生球化。当应变速率为0.001 s~(-1)时,等轴α/α_2相占比较大,且更加细小。弥散分布的细小等轴α/α_2相较好地强化了焊缝。经0.001 s~(-1)应变速率等温锻造后,合金的强度和塑性都得到大幅提高,综合性能匹配较好。
The interface of Ti60 / Ti-22Al-25Nb alloy welding was strengthened by isothermal forging, the effect of strain rate on the structure of base metal and welded joint in isothermal forging process was studied, Conducted at room temperature mechanical properties test. The results show that after isothermal forging, the original coarse dendrite is broken and dynamic recrystallization forms fine equiaxed grains. Segregation formed when welding, holes, inclusions, etc. are compacted or lamination, the organization becomes more closely. The acicular brittle O phase and the martensite α ’phase in the weld are decomposed at high temperature to form α_2 phase and α + β phase respectively, while the α / α_2 phase formed after decomposition is deformed and spheroidized. When the strain rate is 0.001 s ~ (-1), the equiaxed α / α_2 phase takes up a larger proportion and is finer. The fine equiaxed α / α 2 phase dispersion strengthened the weld well. After being isothermally forged at a strain rate of 0.001 s ~ (-1), the strength and ductility of the alloy have been greatly improved, and the overall performance is better matched.