大间隙钎焊用混合粉状高温镍基钎料的润湿性和显微组织

用一种含Al,Ti元素的镍基钎料粉末与γ’相沉淀强化型镍基高温合金FGH95的粉末混合,制备了大间隙钎焊用混合粉状高温镍基钎料。实验表明,采用合适的混合比例,混合粉状钎料对1Cr18Ni9Ti不锈钢具有较好的润湿铺展性。该混合钎料所获得的钎缝金属的合金化效应显著,Al+Ti合金元素的最大含量达到了5.49%。焊态钎缝中,除Nb,W等个别元素外,其他主要强化元素无明显偏析,且经1180℃/4h扩散处理可消除合金元素的偏析。钎缝金属的组织状态较为均匀,基体为等轴γ固溶体枝晶,枝晶间分布有颗粒状、短条状的化合物相以及少量的γ+γ’共晶组织。另外,在γ固溶体中分布着大量弥散细小γ’沉淀强化相。

Wettability and Microstructures of High Temperature Ni-based Mixed Filler Powders for Wide Gap Brazing

High temperature Ni-based mixed filler powders for wide gap brazing were produced by mixing a type of Ni-based high temperature filler powder containing aluminum and titanium and the γ′precipitation strengthened Ni-based superalloy FGH95 powder.The experiment results indicate that the mixed powder filler metals with proper mixing ratio possess good wetting and spreading performances on the stainless steel 1Cr18Ni9Ti.Alloying effects in the brazing metal are considerable,and the maximum total content of aluminum and titanium elements is surprisingly up to 5.49%.The mixed brazing filler metals after high temperature brazing exhibit no remarkable element segregation except niobium and tungsten.After 1180℃/4h diffusion heat treatment,the element segregation is eliminated.The microstructures of the brazing metal are uniform comparatively,and characterized by equiaxed γsolid solution dendrites with interdendritic blocky and short-stripy compounds and a little γ+γ′eutectic,and especially a large amount of fine dispersed γ′precipitation hardening phases distribute in the γ solid solution,as expected.