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为使Inconel 718合金的筒形多层夹芯结构顺利成形,研究该合金激光对接板的高温塑性。结果表明,拉伸方向对激光对接板的伸长率有很大影响。横向拉伸时,在温度为950°C和应变率为3.1×10-4s-1的条件下,最大伸长率为458.56%,此时m值为0.352,焊缝未变形。纵向拉伸时,在温度为965°C和应变速率为6.2×10-4s-1的条件下,最大延长率为178.96%,此时m值为0.261,焊缝随母材同时变形,焊缝的微观组织为树枝晶,晶间析出了Nb含量较高的Laves相。纵向拉伸时,由于动态再结晶的缘故,焊缝中出现了由树枝晶和等轴晶组成的混合组织。高温变形后,焊缝中的大量Laves相转化为δ相,但焊缝中仍有小部分残余的Laves相存在。多层夹芯筒结构成形的结果表明,激光对焊板的高温塑性能满足其筒形夹芯结构的要求。
In order to successfully shape the cylindrical multi-layered sandwich structure of Inconel 718 alloy, the high temperature ductility of the alloy was studied. The results show that the stretching direction has a great influence on the elongation of the laser butt plate. In the transverse drawing, the maximum elongation was 458.56% at a temperature of 950 ° C and a strain rate of 3.1 × 10-4s-1, at which point the m value was 0.352 and the weld was not deformed. Longitudinal stretching, the maximum elongation of 178.96% at a temperature of 965 ° C and a strain rate of 6.2 × 10-4s-1, m value of 0.261, the weld with the base metal deformation at the same time, the weld The microstructure was dendrite, and the Laves phase with high Nb content was precipitated. Longitudinal stretching, due to dynamic recrystallization of the reason, appeared in the weld by dendrites and equiaxed grain mixed organization. After high temperature deformation, a large number of Laves phase in the weld is transformed into δ phase, but there are still some residual Laves phases in the weld. The results of multi-layer sandwich tube structure forming show that the high-temperature plasticity of laser butt-welded plate meets the requirements of its tubular sandwich structure.