CAJ | 학술논문

通过热压采用机械合金化(MA)法合成的合金粉末制备纳米晶块体 Fe-60Ni-15Cr(MA)合金，并与粉末冶金(PM)法制备的常规尺寸Fe-60Ni-15Cr(PM)合金对比，研究两种合金在700~900℃、0.1 MPa纯氧中的氧化行为以及晶粒细化对其氧化行为的影响。结果表明：Fe-60Ni-15Cr(PM)和Fe-60Ni-15Cr(MA)合金的氧化动力学曲线均偏离抛物线规律。在相同温度下，纳米尺寸Fe-60Ni-15Cr(MA)合金的氧化速率明显低于常规尺寸Fe-60Ni-15Cr(PM)合金的。Fe-60Ni-15Cr(PM)合金表面没有形成保护性的Cr2O3膜，而是形成了由Fe的氧化物组成的外氧化膜和由Fe、Ni和Cr氧化物组成的内层，并有合金和氧化物相组成的混合内氧化形成。相反Fe-60Ni-15Cr(MA)合金表面则只形成了保护性的Cr2O3外氧化物膜。因此，晶粒细化有利于降低合金表面形成连续Cr2O3外氧化膜所需Cr的临界含量，促使合金能在较低的Cr含量下形成连续有保护性的Cr2O3外氧化膜。
통과열압채용궤계합금화(MA)법합성적합금분말제비납미정괴체 Fe-60Ni-15Cr(MA)합금，병여분말야금(PM)법제비적상규척촌Fe-60Ni-15Cr(PM)합금대비，연구량충합금재700~900℃、0.1 MPa순양중적양화행위이급정립세화대기양화행위적영향。결과표명：Fe-60Ni-15Cr(PM)화Fe-60Ni-15Cr(MA)합금적양화동역학곡선균편리포물선규률。재상동온도하，납미척촌Fe-60Ni-15Cr(MA)합금적양화속솔명현저우상규척촌Fe-60Ni-15Cr(PM)합금적。Fe-60Ni-15Cr(PM)합금표면몰유형성보호성적Cr2O3막，이시형성료유Fe적양화물조성적외양화막화유Fe、Ni화Cr양화물조성적내층，병유합금화양화물상조성적혼합내양화형성。상반Fe-60Ni-15Cr(MA)합금표면칙지형성료보호성적Cr2O3외양화물막。인차，정립세화유리우강저합금표면형성련속Cr2O3외양화막소수Cr적림계함량，촉사합금능재교저적Cr함량하형성련속유보호성적Cr2O3외양화막。
Nanocrystalline bulk Fe-60Ni-15Cr alloy was prepared by hot pressing alloyed powders synthesized by mechanical alloying (MA) method. High temperature oxidation behavior of the alloy was investigated at 700?900℃in 0.1 MPa pure oxygen,compared with the corresponding coarse grained Fe-60Ni-15Cr alloy prepared by powders metallurgy (PM) technique. The results show that the oxidation kinetics of Fe-60Ni-15Cr(PM) and Fe-60Ni-15Cr(MA) alloys deviate parabolic rate law. At the same temperatures, the oxidation rate of nanocrystalline Fe-60Ni-15Cr(MA) alloy is lower than that of coarse grained Fe-60Ni-15Cr(PM) alloy. Coarse grained Fe-60Ni-15Cr(PM) alloy is unable to form the continuous and protective scales of Cr2O3. In fact, the alloy forms the external Fe oxide scales followed by a layer composed by Fe, Ni and Cr oxides, and there is an internal oxidation in the alloy. On the contrary, nanocrystalline Fe-60Ni-15Cr(MA) alloy is able to form the continuous and protective scales of Cr2O3. It is oblivious that the grain refinement is able to decrease the critical Cr content which is required to form the continuous and protective scales of Cr2O3 and is helpful to form the continuous scales of Cr2O3 under Fe-Ni-Cr alloy surface.