定向凝固铸造高温合金DZ125热处理工艺的研究

Study on Heat Treatment of Directionally Solidified Superalloy DZ125

研究了一步和三步两种热处理工艺对DZ12 5合金组织及性能的影响。结果表明 :采用三步热处理工艺可明显改善显微组织。 1180℃预处理消除了合金中的低熔点相 ,有效地抑制了合金的初熔 ,提高了合金的固溶温度。随着固溶温度的提高 ,元素枝晶偏析减轻 ,共晶中的γ′相和初生的粗大γ′相固溶量增加 ,在随后的冷却和时效过程中析出较多细小γ′相。 110 0℃高温时效调整了细小γ′相的尺寸和形状 ,使合金中温、高温持久寿命比一步热处理有不同程度提高。

The effect of two steps heat treatment on the microstructure and mechanical properties of superalloy DZ125 was studied, Experimental results show that the microstructures change markedly by means of three steps heat-treatment. Ni-5Hf-phase may be eliminated by use of pretreatment of 1180℃ for 2h. The incipient melting of DZ125 superalloy may be effectively controlled. With increasing solution temperature, the dendritic segregation of elements decreased, Eutectic γ′ phase and primary coarse γ′ phase are redissolved continuously into matrix. Fine γ′ phase are reprecipitated during colling and aging. The size and amount of uniform fine γ′ are increased by aging treatment 1100℃ for 4h. The stress-repture life of this alloy increased significantly.