论文部分内容阅读
研究了二代单晶高温合金DD5在980℃无载荷时效处理后的组织及性能变化。结果表明:DD5合金980℃时效后组织基本稳定,5000 h时效后未发现TCP相的析出。980℃时效中,150 h时效后γ’相呈规则立方状并未发生明显长大,平均尺寸达到约0.5μm,1000 h时,γ’相基本呈立方形态分布,但平均尺寸约1μm,2500 h时γ’相粗化明显,5000 h时基本形成筏状组织。时效后,初生碳化物发生分解并有次生碳化物析出,包括点棒状MC(1),块状富Hf的MC(2),细小质点状M23C6。870℃抗拉强度值随时效时间延长逐渐下降,1000 h后下降5.5%,而5000 h后下降9.8%。持久寿命随时效时间延长呈逐渐递减趋势:980℃/207 MPa的持久寿命,1000 h后下降19%,5000 h后下降了43%;1070℃/140 MPa的持久寿命1000 h后下降38%,5000 h后下降了52%;1093℃/158 MPa的持久寿命1000 h后下降31%,5000 h后下降了52%。
The microstructure and properties of the second generation single crystal superalloy DD5 at 980 ℃ without aging were investigated. The results show that the microstructure of DD5 alloy is basically stable after aging at 980 ℃, and precipitation of TCP phase is not observed after 5000 h aging. After aging at 980 ℃, the γ ’phase did not grow obviously in regular cubic shape after 150 h aging, the average size reached about 0.5 μm. At 1000 h, the γ’ phase showed a cubic distribution but the average size was about 1 μm and 2500 When γ h phase coarsening significantly, 5000 h when the basic formation of raft tissue. After aging, primary carbides decompose and secondary carbides are precipitated, including point rod MC (1), massive Hf MC (2) and fine particle M23C. The tensile strength at 870 ℃ gradually increases with aging time Decreased by 5.5% after 1000 h and decreased by 9.8% after 5000 h. The long-term life expectancy decreased gradually with the aging time: the long-term life of 980 ℃ / 207 MPa decreased 19% after 1000 h and 43% after 5000 h; the long-term life of 1070 ℃ / 140 MPa decreased 38% A decrease of 52% after 5000 h; a longevity of 1093 ° C / 158 MPa decreased by 31% after 1000 h and a drop of 52% after 5000 h.