【摘要】 作为高温结构材料，金属钼在高温下的应用受制于抗氧化能力，目前主要通过表面涂层技术或者合金化处理来进行改善。本文采用粉末冶金工艺（干法HfC直接掺杂-球磨-冷等静压-烧结）制备了HfC强化MHC合金，系统研究了其高温氧化特性。研究结果表明：MHC合金的氧化过程呈现明显的温度效应，较低温区间及较短保温时间（<800℃）主要表现为吸氧增重，而高温区间则以挥发失重为主；当温度达到800℃并保温30 min，样品出现4.8%的显著失重，同时表面氧化形貌由初始的氧化脊演变为片层状特征；氧化膜的剥离与氧化脊向片层状特征发展并与界面脱离形成界面孔洞密切相关，这一过程会加速基体的裸露及持续氧化；均匀分布于晶界和晶内的HfC第二相能抑制基体元素的氧化挥发行为。更多还原

【Abstract】 As a high-temperature structural material,the high-temperature application of molybdenum is limited by its oxidation resistance,which is currently improved primarily through surface coating technologies or alloying treatments. This study employed powder metallurgy(HfC direct doping-ball milling-cold isostatic pressing-sintering) to prepare HfC-reinforced MHC alloy and systematically investigated its high-temperature oxidation characteristics. The results show that the oxidation process of the MHC alloy exhibits a distinct temperature dependence. In lower temperature ranges and under shorter holding times(<800 ℃),oxygen absorption and weight gain dominate,while weight loss due to volatilization prevails at higher temperatures. When the temperature reaches 800 ℃ with a holding time of 30 minutes,the sample shows a significant weight loss of 4.8%,accompanied by a transformation of the surface oxide morphology from initial oxide ridges to a layered structure. The spallation of the oxide layer is closely associated with the development of oxide ridges into layered features and their detachment from the interface,leading to the formation of interfacial pores. This process accelerates the exposure of the substrate and promotes continuous oxidation. The HfC second phase,uniformly distributed along grain boundaries and within grains,can effectively suppress the oxidation and volatilization of matrix elements更多还原