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利用金相法、扫描电镜、透射电镜(TEM)等技术研究了镍基耐蚀合金材料固溶时效处理过程中,晶间和晶内大量产生的析出相对材料性能的影响。通过实际摸索试验,对不同温度固溶时效处理以及微观组织变化、析出相出现的条件分析,研究了组织的变化以及析出相对材料性能的影响。结果表明析出相的类型与数量明显受处理温度的影响,析出相大量在晶界产生,几乎呈网状结构;拉伸形貌表明有析出相的断口属于沿晶脆性断裂。结合镍基耐蚀合金在油气田的应用环境,研究了镍基耐蚀合金在酸性环境下的腐蚀性能。碳化物析出相使得晶界形成贫铬区,引起晶内与晶界电位的差异而发生点蚀,点蚀主要集中在晶界处,析出相的存在造成材料耐蚀性下降。建议控制合适的工艺参数,控制碳含量在尽可能低的水平,避免大量析出物的生成影响材料的耐蚀性能。
The effects of precipitation on the properties of materials in the intergranular and intragranular precipitation were studied by means of metallographic method, scanning electron microscopy and transmission electron microscopy (TEM). Through the practical exploration test, the conditions of solution treatment and microstructure change at different temperatures, the analysis of the conditions of the precipitated phase, the changes of the microstructure and the influence of the precipitation on the properties of the material were studied. The results show that the type and amount of precipitated phase are obviously affected by the treatment temperature. The precipitated phase is produced in the grain boundaries in a large amount and almost has a net-like structure. The tensile morphology shows that the fracture with the precipitated phase belongs to the brittle fracture along the crystal. Combined with the application environment of Ni-base corrosion resistant alloy in oil and gas fields, the corrosion behavior of Ni-base corrosion resistant alloy in acid environment was studied. The precipitation of carbides causes the formation of chromium-depleted regions in the grain boundaries, causing pitting corrosion due to the difference in intragranular and intergranular potential. The pitting corrosion mainly concentrates on the grain boundaries and the corrosion resistance of the precipitates decreases. It is recommended to control the appropriate process parameters to control the carbon content as low as possible to avoid the formation of a large number of precipitates affect the corrosion resistance of the material.