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研究了经过高温均匀化固溶处理+中间δ时效处理+双级时效处理的激光立体成形Inconel 718合金的组织及力学性能,并考察了热处理后合金的位错组态.结果表明,由于热处理过程中的再结晶行为,合金组织由沉积态的初始柱状晶转化为等轴晶.Laves相完全固溶,针状δ相以及γ″强化相分别在晶界处以及γ基体上大量弥散析出.激光立体成形Inconel 718合金热处理态的抗拉强度、屈服强度、延伸率以及断面收缩率均达到锻件标准.位错与γ″相的相互作用为位错切割γ″相以及位错绕过γ″相,在位错绕过γ″相的区域,位错密度比位错切割γ″相区域高.由于热处理态δ相尺寸大于锻件,位错会在δ相中发生塞积.碳化物和位错之间也存在强烈的相互作用,通过钉扎和拖曳作用来阻碍位错运动.
The microstructure and mechanical properties of Inconel 718 alloy after laser homogenization and high temperature homogenization solution treatment + middle δ aging treatment + two-stage aging treatment were investigated, and the dislocation configurations of the alloy after heat treatment were investigated.The results show that due to the heat treatment process , The alloy structure transformed from the initial columnar crystals into equiaxed grains.The Laves phase was completely dissolved and the acicular δ phase and the γ “strengthening phase were diffused out at the grain boundaries and γ matrix respectively. The tensile strength, yield strength, elongation and reduction of area of the as-formed Inconel 718 alloy all reach the forging standard.The interaction between dislocation and γ ”phase is the dislocation cutting γ“ phase and the dislocation bypass γ ”phase , The dislocation density is higher than the dislocation-cut γ “-phase in the region where the dislocation bypasses the γ” phase. Due to the larger δ phase size than the forgings in the heat treatment, dislocations are plugged in the δ phase. There is also a strong interaction between the pinning and drag to impede the dislocation movement.