激光快速成形Inconel 718超合金拉伸力学性能研究

研究了激光快速成形Inconel 718超合金试样3个相互垂直方向的拉伸力学性能,以及热处理对激光快速成形凝固组织与3个相互垂直方向拉伸力学性能的影响。结果表明,激光快速成形Inconel 718超合金试样3个相互垂直方向的拉伸力学性能均明显低于其锻件拉伸力学性能,且表现出明显的各向异性。经过热处理的Inconel 718超合金试样,其沿沉积高度方向定向外延生长的柱状枝晶组织转变为晶粒粗大且不均匀的等轴状再结晶组织,随Laves相固溶消失及强化相γ″和γ′大量析出,3个相互垂直方向上的拉伸力学性能均大幅度提高,其中,与基板平行的两个相互垂直方向上的拉伸力学性能均达到Inconel 718超合金锻件拉伸力学性能标准,但沿成形件高度方向,出现拉伸力学性低于Inconel 718超合金锻件拉伸力学性能标准的试样。

Research on Tensile Properties of Inconel 718 Superalloy Fabricated by Laser Rapid Forming Process

The tensile mechanical properties in three mutually perpendicular directions of Inconel 718 superalloy sample fabricated by laser rapid forming (LRF) are studied. The influences of heat treatment on both the solidification microstructures of and the tensile mechanical properties in three mutually perpendicular directions of Inconel 718 superalloy sample are investigated. It is shown that the tensile mechanical properties of all test specimens are clearly inferior to that of wrought Inconel 718 superalloy. After being heat treated, the coarse columnar dendrites growing epitaxially along the deposition direction of as-deposited Inconel 718 superalloy change to the coarse and non-uniform equiaxed grains due to recrystallization. With the dissolution of Laves phase and precipitation of a large number of strengthening phase γ″ and γ′, the tensile mechanical properties in three mutually directions increase substantially. The tensile properties of tested specimens whose tensile directions are parallel with the base plate reach the tensile properties standard of wrought Inconel 718 superalloy. There are also tested specimens whose tensile mechanical properties in the direction perpendicular to the base plate not meeting the tensile properties standard of wrought Inconel 718 superalloy.