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对GH738镍基高温合金贯通槽式损伤试样进行激光沉积修复,分析了修复试样的显微组织及室温拉伸性能。结果表明:激光沉积修复区组织为典型的外延生长柱状枝晶,枝晶垂直于基体,并趋向激光沉积高度方向贯穿多个沉积层连续生长,修复区中心的枝晶取向出现了较大偏转;修复区内未发现γ′相,且碳化物含量较少,枝晶干上主要为富含Cr、Co的颗粒状M_(23)C_6型碳化物,枝晶间存在少量尺寸相对较大的立方体MC型碳化物,其Ti、Mo含量较高。相比于基体,热影响区中γ′相的尺寸明显增大,部分尺寸超过了200nm,平均间距明显增大;热影响区内的碳化物含量减少,且部分碳化物发生分解。激光沉积修复试样的室温抗拉强度为锻件的78.2%,断后伸长率为锻件的69.2%。
GH738 nickel-based superalloy through the groove damage specimens laser deposition repair, analysis of the repaired specimen microstructure and tensile properties at room temperature. The results show that the laser repaired zone is a typical epitaxial growth dendrite. The dendrites are perpendicular to the substrate and grow toward the height of the laser deposition continuously through multiple sedimentary layers. The dendrite orientation in the center of the repaired area shows a large deflection. The γ ’phase was not found in the rehabilitated area, and the content of carbides was small. The dendrites mainly consisted of Cr, Co-rich granular M_ (23) C_6 carbides with a small number of cubes MC type carbide, its Ti, Mo content is higher. Compared with the matrix, the size of γ ’phase in the heat affected zone obviously increases, the part size exceeds 200nm and the average spacing increases obviously. The content of carbides in HAZ decreases and some carbides decompose. The tensile strength at room temperature of the laser deposition repaired sample is 78.2% of the forging and the elongation at break is 69.2% of the forging.