摘要
研究了双极时效热处理对激光沉积修复GH738合金显微组织及力学性能的影响。结果显示:沉积态显微组织为典型的外延柱状枝晶,枝晶间距约为10μm。经过时效处理后,修复区组织开始长大、合并。沉积态未发现γ′相,枝晶间存在立方状的MC型碳化物,枝晶干存在颗粒状M_23C_6型碳化物。经双级时效处理后,修复区析出γ′相:稳定化温度为820℃时,γ′相平均尺寸约为37 nm,碳化物在晶界处呈断续状析出。随着稳定化温度升高,γ′相及碳化物尺寸均有所增大,其中稳定化温度为840℃时,γ′相平均尺寸约为76 nm,碳化物呈项链状析出;稳定化温度为860℃时,γ′相平均尺寸无明显增大,部分γ′相发生明显粗化,尺寸达到150 nm,晶界处碳化物开始呈包膜状析出。力学性能测试结果显示:时效处理后试样抗拉强度明显提高,随着稳定化温度升高,抗拉强度先升高后降低,断后伸长率不断降低。
The effects of bipolar aging heat treatment on the microstructure and mechanical properties of GH738 alloy repaired by laserdeposition were studied. The results show that the microstructure of repair area presents typical characteristics of the epitaxial growth ofcolumnar crystals and the dendrite spacing is about 10 μm. After the aging treatment, the repair area begins to grow and merge. The resultsof SEM analysis show that there is no γ′ at the as-deposited sample, and the cubic MC type carbide is formed at the interdendritic, and theM23C6 type carbide at the dendrite arm. After the aging treatment, γ′ phase precipitates at the repair area whose average size is 37 nm, andthe carbide precipitates in the grain boundary with the discontinued character when the temperature of the stabilization step is 820 °C. Withthe increase of the stabilization temperature, the size of the γ′ and carbide increases. When the temperature is 840 °C, the average size ofthe γ′ is about 76 nm, and the carbide is precipitated in the form of necklace. With increasing the temperature of the stabilization step to 860 °C, the average size of the γ′ does not increase obviously, and part of the γ′ is obviously coarsened and the size reaches to 150 nm;meanwhile the carbides at the grain boundaries begin to be closed. The results of mechanical property show that the tensile strength of thesample increases obviously after aging treatment, and with the increase of the temperature, the tensile strength increases first and thendecreases, and the elongation decreases continuously.
作者
卞宏友
翟泉星
曲伸
杨光
王伟
王维
Bian Hongyou;Zhai Quanxing;Qu Shen;Yang Guang;Wang Wei;Wang Wei(Key Laboratory of Fundamental Science for National Digital Manufacturing Process, Shenyang Aerospace University,Shenyang 11013 6,China;Shenyang Liming Aero-Engine Corporation LTD,AECC,Shenyang 110043,China)
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2019年第1期317-322,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51375316)
航空科学基金(2014ZE54028)
辽宁省自然科学基金(20170540690)
关键词
激光沉积修复
GH738合金
热处理
显微组织
力学性能
laser deposition repair
GH738 alloy
heat treatment
microstructure
mechanical properties
