哈氏C-2000合金在等温氧化时第二相沉淀析出行为

Precipitation behavior of second phases during isothermal oxidation of Hastelloy C-2000 alloys

摘要:

研究了哈氏C2000合金在800℃100h空气中等温氧化后合金基体中第二相的沉淀行为。氧化后基体中析出了富Mo相，可确定该富Mo相为具有金刚石结构的Mo3Ni3C型碳化物。富Mo相沿晶界和晶内分别呈现出非连续和连续条状形貌特征。然而，经深腐蚀后，晶内和晶界处形貌均发生了变化，即，沿晶界出现了大量白色絮状物，晶内则出现了具有金刚石结构的腐蚀坑。由于富Ni和富Cr区域具有更负的电极电位，因而使得这些区域在深腐蚀后更易被侵蚀。

Abstract:

The precipitation behavior of second phases in Hastelloy C-2000 alloy matrix was studied after isothermal oxidation at 800 oC for 100 h in air. Mo-rich phases were precipitated in the alloy matrix after oxidation. It is determined that Mo-rich phases with diamond cubic structure are Mo3Ni3C type carbides. Morphology characteristics of Mo-rich phases with both no-continuous irregular strip and continuous were presented along grain boundaries and in matrix, respectively. However, some variation of morphologies will take place at both grain and grain boundaries after deep etching, i.e., a large number of white flocculent structure were distributed along grain boundaries, and corrosion pits with a diamond structure appear in intragranular. Areas of Ni and Cr-rich are more easily corroded during deep etching due to a more negative electrode potential in areas.