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涡轮发动机涡轮盘合金的低周疲劳寿命取决于疲劳裂纹的萌生和扩展。先进的净化熔炼技术可以改善合金的性能,减小缺陷的尺寸,从而得到新一代抗疲劳断裂的高强度高温合金。只有弄清高强度高温合金中产生疲劳裂纹的机理和显微组织与性能之间的相互关系,通过冶金方法控制疲劳裂纹扩展才有可能。控制合金抗高温疲劳的许多冶金参数现已弄清。对于所有高γ′含量的高温合金,最有效的冶金控制方法是在γ′溶解度线以上温度进行固溶处理后控制冷却速度,以改善晶粒边界的显微组织。冷却时,在晶粒边界发生的沉淀反应产生锯齿形的组织,这种组织有良好的抗疲劳裂纹的应力-氧化腐蚀性能。
The low cycle fatigue life of turbine disk turbine disks depends on the initiation and propagation of fatigue cracks. Advanced purification smelting technology can improve the performance of the alloy, reducing the size of defects, resulting in a new generation of high-strength high-temperature fatigue fracture resistance of high-temperature alloys. Only by clarifying the mechanism of fatigue cracking in high-strength superalloy and the correlation between microstructure and properties, it is possible to control fatigue crack propagation through metallurgical methods. Many metallurgical parameters that control the fatigue resistance of alloys are now clear. For all high γ ’superalloys, the most effective metallurgical control method is to control the cooling rate after solution treatment at a temperature above the γ’ solubility line to improve grain boundaries’ microstructure. When cooled, the precipitation reaction at the grain boundaries produces zigzag-shaped structures that have good stress-oxidation corrosion resistance to fatigue cracks.