论文部分内容阅读
研究了一种Fe-Cr-Ni-Ti铸造高温合金在700～300℃范围内10分钟～500小时的氧化动力学。氧化增重符合抛物线规律;氧化凹坑深度的发展符合直线规律。氧化激活能Q_(P1)=38kcal/mol,Q_(P2)=42kcal/mol。短时氧化膜富Fe、Ti、Cr,主要由Fe_2O_2、TiO_2和Cr_2O_2组成;长时间氧化层主要由NiTi O_3和Fe Cr_2 O_4组成。氧化过程中,阳离子空位相互结合形成空穴,穴长大连接成空穴带,它是氧化层剥落的裂纹源。不均匀氧化剥落凹坑是η-Ni_3Ti或γ′-Ni_2(Al、Ti)选择性氧化所致。较高的含Ti量阻碍Cr_2O_3的形成,促进了尖晶石类型氧化物的形成,使合金抗氧化性能下降。
The oxidation kinetics of Fe-Cr-Ni-Ti foundry superalloy at 700-300 ℃ for 10 min to 500 h was studied. Oxidation weight gain complies with the law of parabola; the development of oxidation pit depth accords with the law of straight line. The oxidation activation energy Q_ (P1) = 38 kcal / mol, Q_ (P2) = 42 kcal / mol. The short-time oxide film is rich in Fe, Ti, Cr and mainly consists of Fe 2 O 2, TiO 2 and Cr 2 O 2. The long-time oxide layer mainly consists of NiTi O 3 and Fe Cr 2 O 4. Oxidation process, the cation vacancies combined with each other to form holes, hole growth connected to a hole zone, it is the source of oxide flaking cracks. Uneven oxidation exfoliation pits are caused by the selective oxidation of η-Ni_3Ti or γ’-Ni_2 (Al, Ti). The higher content of Ti hinders the formation of Cr 2 O 3 and promotes the formation of spinel-type oxides, which leads to the decrease of the oxidation resistance of the alloy.