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研究了长期时效对低碳Ni-Cr-W-Mo耐热合金组织和力学性能的影响。结果表明,长期时效后低碳Ni-Cr-W-Mo耐热合金存在3种析出相:M6C型初生碳化物相、二次M23C6型碳化物相和μ相;其中M6C型初生碳化物相存在于供应态和时效态。因为合金含碳量低,所以合金在750℃时效超过200h和在900℃时效超过100h时,就析出μ相。合金在750℃时效至1 000h时,随着时效时间的延长,合金硬度值不断增加;而合金在900℃时效至1 000h时,随着时效时间的延长,合金硬度值首先增加至最大值,随后合金硬度值随着时效时间的延长而降低;这是因为二次M23C6型碳化物析出形态在时效过程中发生了变化。合金时效前后的室温拉伸性能数据证实微量μ相对合金室温拉伸影响很小。
The effects of long-term aging on the microstructure and mechanical properties of low carbon Ni-Cr-W-Mo heat-resistant alloys were investigated. The results show that there are three kinds of precipitates in the low-carbon Ni-Cr-W-Mo heat-resistant alloy after long-term aging: M6C primary carbide phase, secondary M23C6 carbide phase and μ phase. Among them, M6C primary carbide phase In the supply and aging state. Because of the low carbon content of the alloy, the alloy precipitates the μ phase when aged at 750 ° C for more than 200 hours and aged at 900 ° C for more than 100 hours. When aging at 750 ℃ for 1 000h, the hardness of the alloy increases with the aging time. The hardness of the alloy first increases to the maximum with aging time at 900 ℃ to 1000h, The alloy hardness then decreases with the aging time; this is because the secondary M23C6 carbides precipitated in the aging process has changed. Tensile properties at room temperature before and after the aging test data show that micro-μ relative to the alloy tensile at room temperature has little effect.