固溶处理对长期服役燃机透平叶片组织和力学性能的影响

Effect of solution treatment on microstructure and mechanical properties of turbine blade after long-term service

对服役约27000 h的重型燃机透平一级动叶进行了1180℃×2 h/ArC(ArC:吹氩冷却)固溶处理,对比分析了此GTD111合金叶片不同区域的微观组织和力学性能变化。结果表明,叶片前缘区和中部区保持着树枝晶形态,晶界、碳化物及γ′相无明显老化。而尾缘区树枝晶消失,晶界存在粗化,碳化物明显退化,γ′相发生了粗化和筏化。叶片尾缘区硬度整体上高于前缘,在25~871℃下叶顶到榫头试样的抗拉强度总体上呈先增加后降低的趋势,而在982℃下不同位置试样的抗拉强度趋近相同。对于服役后的GTD111合金透平叶片,1180℃下固溶处理未能完全消除老化组织,与固溶温度较低或保温时间不足有关。

A first stage rotor blade made of GTD111 alloy in heavy gas turbine after service for 27000 h was solution treated at 1180℃for 2 h and then argon blowing cooled,the microstructure and mechanical properties of different regions of the blade were compared and analyzed.The results show that dendrite morphology is maintained in the leading edge and middle region of the blade,meanwhile grain boundaries,carbides andγ′phase are not aged obviously.In the trailing edge of the blade,however,the dendrites disappear,the grain boundaries are coarsened,the carbides degrade obviously,and theγ′phase is coarsened and rafted.The hardness of trailing edge in the blade as a whole is higher than that of leading edge,the tensile strength of the specimens varying from blade tip to tenon increases first and then decreases on the whole at 25-871℃,while that of the specimens at different positions tends to be the same at 982℃.For the GTD111 alloy turbine blades after long-term service,the solution treatment at 1180℃cannot completely eliminate the aged microstructure,which is related to the insufficient solution temperature or holding time.