(中南大学 粉末冶金国家重点实验室，长沙 410083)
摘 要: 采用粉末冶金方法制备纯钼和MT钼合金，研究纯钼及MT合金在1 200 ℃的氧化行为和氧−乙炔焰烧蚀行为。结果表明：纯钼从晶界或孔隙等缺陷处开始氧化，逐步向内和周围侵蚀，生成易挥发的氧化钼，氧化钼的挥发使得纯钼在整体上以层片状逐步氧化，并且质量损失明显。MT合金中添加的超高温轻质相和合金元素能够形成耐高温、热稳定性优异的氧化物，生成的氧化物会在基体表面形成氧化物覆盖层，可以有效地阻碍氧向基体的侵入，从而使MT合金的抗氧化性和抗烧蚀性能提高，其氧化质量损失率仅为纯钼的1/3，并且在120 s的氧−乙炔焰烧蚀下，其线烧蚀率仅为0.17×10−3 mm/s。
关键字:
refractory alloy at high temperature
（State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China）
Abstract:The pure molybdenum and MT alloys were prepared by powder metallurgy process. The oxidation behavior and ablation behavior in oxyacetylene of pure molybdenum and MT alloys at 1200℃ were studied. The results indicate that the oxidation of pure molybdenum arises from defects such as grain boundaries or pores, then it corrodes the inside and ambient area gradually, forming volatile molybdenum oxide, whose volatilization causes the step by step oxidation of pure molybdenum as a whole and significant mass loss. The ultra-high-temperature light phase and alloying elements added into the MT alloys can form high-temperature oxidation coatings with excellent thermal stability on the matrix surface, and can obstruct the intrusion of oxygen to the substrate. As a result, the oxidation resistance and ablation resistance of MT alloys increase, its oxidation mass loss is only 1/3 of that of pure Mo, the linear ablation rate in oxyacetylene for 120 s is just 0.17×10−3 mm/s.
Key words: molybdenum alloy; oxidation resistance; oxidation mechanism; ablation behavior
