Ti—13Al—29Nb—2.5Mo合金ISM熔炼过程中多组元挥发损失

Evaporation Loss of the Components in Ti-13Al-29Nb-2.5Mo Melt during ISM Process

摘要:

在基于活度系数计算模型的基础上，计算了ISM熔炼过程中不同熔炼温度下Ti-13Al-29Nb-2.5Mo(ω/%)熔体中Ti,Al,Nb元素的饱和蒸气压，计算结果表明，在熔炼温度范围内，Al元素的饱和蒸气压分别比Ti,Nb元素的饱和蒸气压大17倍和3070倍左右。在熔炼温度范围内对熔体中Al,Ti,Nb元素的挥发损失速率的计算表明，Al元素在损失速率比Ti,Nb的损失速率分别大43倍和144倍左右，在此基础上计算了Ti,Al,Nb元素的挥发损失量以及合金在熔炼后的化学成分，结果表明由于合金中各组元的挥发损失速率大小不一，使得熔炼前后合金的成分出现了变化。分析表明合理降低熔炼温度及增加真空室中压力可以减小成分的变化。本结果为ISM熔炼实践中合金成分控制提供有价值的理论指导。

Abstract:

Based on the activity coefficient calculation module, the saturated pressures of Ti, Al and Nb elements in molten Ti-13Al-29Nb-2.5Mo (mass fraction) at different melting temperatures were calculated. The saturated pressure of element Al in the melting temperature is as big as 17 and 3 070 times of those of Ti and Nb elements respectively. The mass loss rates of Al, Ti, Nb in the melt during the process were also calculated. The mass loss rate of Al is as big as 43 and 144 times of those of Ti, Nb. Based on the evaporation loss rate, the evaporation loss quantity of the elements and the alloy chemical composition after the ISM process was also calculated. Because the mass loss rates of Al, Ti and Nb are different, the ultimate alloy chemical composition deviated from its original composition after the melting process. Analysis shows that properly decreasing the melting temperature and/or increasing the chamber pressure can decrease the composition deviation. This article will give some valuable guidance to the alloy composition controlling during ISM process.