复合阻隔镀层对钒合金与不锈钢电子束焊接头组织与性能的影响

Effect of composite isolation coatings on microstructure and properties of electron beam welding joint for vanadium alloy and stainless steel

钒基合金被公认为是理想的聚变反应堆结构材料,为了更有效和经济地利用钒基合金,需要将钒合金与不锈钢进行连接。通过电镀Ni+Au作为复合中间层,采用电子束阻隔熔化焊方法来实现V-5Cr-5Ti钒合金与HR-2不锈钢之间的连接。结果表明:电子束流偏向钒合金一侧焊接得到的钒合金与不锈钢接头界面将产生贯穿性裂纹,直接导致焊接失败。电子束流偏向不锈钢一侧,电镀Ni+Au作为界面阻隔层,很好地抑制了V/Fe界面的金属间化合物的产生,显著提高了接头性能,接头抗拉强度最高达到430 MPa。电子束阻隔熔化焊得到的钒合金/不锈钢异种金属焊接接头焊缝正反面成形良好,X射线探伤未发现裂纹和气孔缺陷。

Vanadium base alloy has been considered as leading candidate for fusion energy systems.To construct more effective and economic system,dissimilar materials joints between vana-dium alloy and stainless steel are required.The high vacuum electron beam isolation welding(EBIW)was used to join vanadium alloy(V-5Cr-5Ti)to stainless-steel(HR-2)with the composite coatings Ni+Au.The results show that with EB off-set to the vanadium alloy side,the penetrating crack formed in the interface of joint between vanadium alloy and stainless steel,which directly lead to welding failure.And with EB off-set to the stainless steel side,electroplated Ni+Au composite coatings as good isolation layer,well inhibited the generations of intermetallic compounds at the V/Fe interface,and significantly improved the weld quality.The maximum tensile strength of EBIW joint of vanadium alloy/Ni+Au/stailess-steel is up to 430MPa.The vanadium/stainless steel dissimilar metal welded joints obtained by EBIW have good appearance of both sides of the welds,and there is no crack and porosity defect detected in the joints through X-ray inspection.