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对GH4169合金锻件与激光成形修复(LFR)件进行显微组织观察和持久性能实验。结果表明:锻造GH4169合金组织为等轴晶,在晶界和晶内弥散析出颗粒状或短棒状δ相,可有效阻碍位错运动以及降低裂纹扩展速率;激光修复GH4169合金经直接双级时效处理(DA)后,与沉积态相比,组织特征变化不大,呈现为沿沉积方向外延生长的柱状枝晶,枝晶间仍然存在块状Laves相,Laves相作为一个脆性相,为裂纹的起源和扩展提供了有利的位置和通道。锻件试样经受高温持久载荷时的断裂机制表现为微孔聚集型断裂,其中δ相、碳化物(MC)是微孔形成的核心,并且断裂后留下了形状与尺寸各异的韧窝组织。激光修复试样经受高温持久载荷时断裂发生在修复区一侧,韧窝以枝晶间Laves相和MC为形核中心,因此留下了以枝晶间区域为韧窝中心和以枝晶干区域为撕裂棱的韧窝组织。
GH4169 alloy forgings and laser forming repair (LFR) pieces of microstructure observation and durability performance experiments. The results show that the forged GH4169 alloy is equiaxed and the granular or short rod δ phase precipitated in the grain boundaries and grains, which can effectively impede the dislocation movement and reduce the crack growth rate. The laser-repaired GH4169 alloy is directly double-stage aged (DA), compared with the as-deposited state, the microstructures did not change much and presented as columnar dendrites growing epitaxially along the deposition direction. Laves phase remained as a brittle phase between dendrites, which was the origin of cracks And expansion provides a favorable location and access. The fracture mechanism of the forged specimens when they were subjected to sustained loading under high temperature showed micro-pore aggregated fracture, in which the δ-phase and the carbide (MC) were the core of the micro-pores and fractured the dimples with different shapes and sizes . When the laser-repaired specimen was subjected to sustained high temperature load, the fracture occurred on the side of the repair area, and the dimples were centered on the Laves phase and the MC of the dendrite, thus leaving a dendritic area centered between the dendrite and the dendrite The area is tear dimpled dimples.