纯净化制备对DZ125L合金组织和力学性能的影响

Effect of Purified Smelting Method on Microstructure and Mechanical Properties of DZ125L Superalloy

摘要:

通过普通熔炼和纯净化工艺分别制备不同O，N，S，P等杂质元素含量的定向凝固镍基高温合金DZ125L。采用金相显微镜、扫描电镜等方法对不同杂质元素含量合金的微观组织进行观察和分析，并测定不同合金的拉伸、持久、蠕变、疲劳等性能。研究结果表明，纯净化制备方法可以进一步降低DZ125L合金中O、N、S、P的含量，使各杂质元素含量均由0.0010%左右降至0.0005%以下，合金纯净度得到改善；随着合金纯净度的提高，合金中疏松和夹杂物的含量进一步降低；纯净化工艺制备的DZ125L合金室温及760℃、850℃和980℃下的抗拉强度和屈服强度得到一定改善，合金760℃/800MPa、850℃/560MPa及980℃/250MPa的持久寿命得到提升，而1040℃/150MPa持久寿命变化不大；随着杂质元素含量的降低，DZ125L合金950℃不同应力下的蠕变变形速度减缓，而760℃高周拉压疲劳寿命得到较大提升。

Abstract:

Different contents of impurity elements such as O, N, S and P of DZ125L superalloy were obtained through ordinary smelting method and purified smelting method, separately. The microstructures of experimental alloy were investigated by optical microscopy and scanning electron microscopy, the mechanical properties of alloy were also measured. Results show that the contents of O, N, S and P of DZ125L alloy can be reduced from 0.0010% to 0.0005% by purified smelting method, and the contents of shrinkage and inclusions are decreased with increment of the purity of DZ125L. The yield strength and tensile strength at room temperature, 760℃, 850℃ and 980℃ are slightly improved in alloy produced by purified smelting method, while the stress rupture properties at 760℃/800MPa, 850℃/560MPa and 980℃/250MPa are improved dramatically. The creep properties at 950℃ and fatigue properties at 760℃ can also be enhanced by purified smelting method.