铸造Ti60氧化形貌的研究

Study on Oxidation Morphology of As-cast Ti60 Alloy

为了研究铸造Ti60的高温氧化形貌,采用熔铸法制备了Ti60合金铸锭,并利用金相显微镜、电子天平、SEM研究了铸态Ti60的金相组织,在不同加热温度保温5h的氧化增重和表面形貌。结果表明,铸态Ti60的金相组织为针状(α+β)+少量富钕颗粒;在700℃-1100℃,随着加热温度的升高,铸造Ti60氧化加重,形成氧化钛膜;700℃-900℃,试样增重只有0.110%-0.609%;1100℃氧化增重严重,达到9.137%;钛的氧化增重为吸氧。铸态Ti60试样表面形貌,700℃氧化钛膜很薄较致密;900℃试样表面有较多的白色颗粒和少量腐蚀坑,表面不致密;1000℃形成片状和块状TiO2;1100℃氧化层为厚大块状的TiO2。氧化过程为高温时,氧化膜粗大变得疏松多孔,氧通过氧化膜扩散进基体。

In order to study oxidation morphology of as-cast Ti60 alloy at high temperature, Ti60 ingot casting was fabricated by melting-casting and its metallurgical structure, oxidation weight gain and surface morphology at different temperature for 5 hour were investigated by means of metalloscope, electronic balance, SEM. Results showed that the structure of the as-cast Ti60 are composed of acicular ct and ~ with a few particles rich in neodymium. With increase in heated temperature at 700 ℃-1100℃, the oxidation weight gain of Ti60 increased by formation of TiO2 film at 700 ℃-900 ℃, the oxidation weight gain for samples ranged only from 0.110 % to 0.609 %. At 1100 ℃, the oxidation weight gain reached 9.137 % caused by oxygen absorption. As shown in SEM, the TiO2 film on the casting Ti60 was quite thin and denser at 700℃. There were many white particles and a few etch pits on the surface at 900 ℃. The flaky and blocky TiO2 layer formed at 1000 ℃, and thick blocky TiO2 at 1100 ℃. The coarse grains of TiO2 film became porous and the oxygen diffused into the substrate through this film at high temperature.