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采用TIG焊对MGH956合金进行原位合金化焊接,研究了B4C对焊缝显微组织和力学性能的影响。结果表明,填加B4C后焊缝以等轴晶为主,晶粒细小均匀,没有明显的氧化物聚集现象,晶内和晶界都有增强相;随着B4C含量的提高焊缝组织进一步细化,增强相几乎全部集中在晶界上,晶内颗粒状增强相消失。随着B4C含量的提高焊缝的塑韧性降低,抗拉强度先增大后降低。填加0.25%B4C时焊缝抗拉强度最高,达到630 MPa,为母材强度的87.5%,断口呈脆性断裂。
In-situ alloying welding of MGH956 alloy was carried out by TIG welding. The effect of B4C on the microstructure and mechanical properties of the weld was studied. The results show that the weld is mainly equiaxed with B4C, the grains are fine and uniform, there is no obvious phenomenon of oxide aggregation, and both the grain boundary and the grain boundary have the enhanced phase. With the increase of B4C content, the weld microstructure is further thinned Almost all of the enhancement phase and the enhancement phase are concentrated on the grain boundary, and the intragranular granular reinforcing phase disappears. With the increase of B4C content, the plasticity and toughness of the weld decreased, the tensile strength first increased and then decreased. When 0.25% B4C is added, the tensile strength of the weld is the highest, reaching 630 MPa, which is 87.5% of the base metal strength, and the fracture is brittle fracture.