对GH4199合金进行不同时间的高密度电脉冲处理,研究高密度电脉冲下合金组织的演化及处理后的拉伸性能。结果表明,高密度电脉冲显著加速合金中原子的扩散,与常规时效状态相比,γ′相的长大激活能(89.86kJ/mol)降低64.31%,使γ′相及晶界碳化物的析出及长大速度加快。高密度电脉冲处理使合金强度随处理时间的延长而提高,塑性无显著变化。脉冲电流下γ′相的长大及晶界碳化物的析出是阻碍位错运动、提高塑性变形抗力的主要原因;而晶界碳化物呈链状分布,塞积位错可以通过碳化物间隙穿过晶界,使合金塑性未明显劣化。
GH4199 alloy was treated by high density electropulsing for different time,and the microstructure evolution and tensile properties were examined.The results show that the diffusion of solute atoms in GH4199 alloy can be strongly accelerated by electropulsing.The growth activation energy of γ' phase of 89.86 kJ/mol in the alloy electropulsing-treated,decreases by 64.31 % compared with that normally aged,which accelerates the precipitation and the growth of both the γ' phase and carbides on the grain boundary of the alloy.The strength of GH4199 alloy increases with increasing of electropulsing treatment time,and the plasticity has no obvious change.The growth of γ' phase and the precipitation of carbides on the grain boundary is the main reason for obstructing the dislocation motion and improving the plastic deformation resistance of the alloy.The piled-up dislocations can go through the grain boundary across the gap of carbides which is distributed on the grain boundary in chainlike form,and no degradation of the plasticity of GH4199 alloy appears.