Inconel 625合金温敏特性对高温力学性能的影响
发布时间：2018-12-30 13:55
【摘要】：得益于Inconel 625合金良好的耐腐蚀、抗氧化性能及较高的高温强度,其常被用于核电、化工、军事以及海洋等领域。镍基高温合金由于合金化种类繁多,成分复杂,在高温载荷复合作用的服役环境下,其高温力学性能会在较窄的温度区间内发生明显的变化。本课题将上述特性界定为Inconel 625合金的温度敏感特性。本课题以Inconel 625合金温敏特性为切入点,通过设计不同参数下的高温拉伸实验以及不同温度下的高温蠕变实验,研究合金抗高温拉伸与蠕变性能以及对应的组织演化规律与温度因素的内在关联机制。在不同温度高温拉伸实验中发现Inconel 625合金抗拉强度在650~700℃温度区间内呈上升趋势,异于高温合金抗拉强度随温度变化的普遍规律。在随后的微观组织观察中发现,合金晶粒内富铬M23C6碳化物以及富铌MC型碳化物在700℃温度区间内发生了分解,分别由大块立方体和不规则块体分解为小块状立方体和层片状块体。在700℃时,由于碳化物的分解产生了质点弥散强化效应从而导致合金抗拉强度提升。本课题将引发碳化物的分解的原因推断为应力诱导碳化物分解。在不同应变速率高温拉伸实验中发现,合金高温力学性能参数与应变速率关联性并不高,随应变速率的升高,合金的屈服强度、抗拉强度等参数的变化均为表现出明显的规律性。在微观组织观察中发现,随应变速率上升,晶界处富铬M23C6型碳化物析出形貌由不连续的球块状向连续的颗粒状转变。在Inconel 625合金固溶处理实验中发现,当固溶温度达到1170℃时,晶粒明显长大,此时平均晶粒尺寸为79μm。在随后的高温拉伸实验中发现,随固溶温度升高,试样延伸率降低,与室温拉伸实验结果相反。除固溶温度1130℃下的试样抗拉强度接近未经固溶处理拉伸试样外,其他固溶温度下的试样抗拉强度均低于未经固溶处理拉伸试样,且随固溶温度上升,试样抗拉强度下降。在微观组织观察中发现,δ相在拉伸温度为700℃析出,随着固溶温度的升高,δ相尺寸及数量也随之增加并导致合金高温塑性下降。在不同温度高温蠕变实验中发现,Inconel 625合金在不同蠕变温度下表现出了较为明显的温度敏感特性,当蠕变温度低于750℃时,试样长时间处于初始蠕变阶段。当蠕变温度高于750℃时,试样出现了完整的蠕变三阶段,当蠕变温度升至800℃,稳定蠕变阶段急剧缩短。在对微观组织观察中发现,随蠕变温度升高,δ相析出量增大,且沿晶界向晶内以针状形式生长。δ相的析出及生长降低了合金的高温抗蠕变性能,导致在800℃时合金抗蠕变性能急剧下降。
[Abstract]:Inconel 625 alloys are widely used in nuclear, chemical, military and marine fields due to their good corrosion resistance, oxidation resistance and high temperature strength. Because of the variety of alloying and complex composition, the mechanical properties of nickel-based superalloys will change obviously in a narrow temperature range in the service environment of high temperature load. In this paper, the above characteristics are defined as the temperature sensitive properties of Inconel 625 alloy. In this paper, the temperature sensitive characteristics of Inconel 625 alloy are taken as the breakthrough point, and the high temperature tensile test and creep experiment at different temperature are designed. The relationship between the tensile and creep properties of the alloy at high temperature and the relationship between the microstructure evolution law and the temperature factors was studied. The tensile strength of Inconel 625 alloy was found to be increasing in the temperature range of 650 ~ 700 鈩，
本文编号：2395669
[Abstract]:Inconel 625 alloys are widely used in nuclear, chemical, military and marine fields due to their good corrosion resistance, oxidation resistance and high temperature strength. Because of the variety of alloying and complex composition, the mechanical properties of nickel-based superalloys will change obviously in a narrow temperature range in the service environment of high temperature load. In this paper, the above characteristics are defined as the temperature sensitive properties of Inconel 625 alloy. In this paper, the temperature sensitive characteristics of Inconel 625 alloy are taken as the breakthrough point, and the high temperature tensile test and creep experiment at different temperature are designed. The relationship between the tensile and creep properties of the alloy at high temperature and the relationship between the microstructure evolution law and the temperature factors was studied. The tensile strength of Inconel 625 alloy was found to be increasing in the temperature range of 650 ~ 700 鈩，
本文编号：2395669
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