Effect of Solid Solution Heat Treatment and Aging on Microstructure of K465 Alloy

The microstructure and mechanical properties of K465 as cast alloy,after solid solution heat treatment and ageing at high temperature,had been investigated.Resultsrevealed that the volume fraction of cube-shaped γ' phase in the dendrite core was 62% for K465 after solid solution heat treatment,fine MC-type carbide was precipitated in the dendrite core,and there presented M₆C carbide transformed from MC carbide. The needle and stick-like secondary phases riched in W and Mo precipitatd after the alloy ageing at 1 000℃ for 500 h and 1 100℃ for 100 h. The amount of secondary precipitates increased over the ageing time at 1 000℃; the elevated temperature promoted the growth of secondary precipitates.