喷射成形高温合金沉积坯致密度与气体含量

雾化沉积坯常含有一定量的疏松.本文对雾化沉积坯的致密度、疏松尺寸、气体含量及其分布等进行了分析研究,同时对雾化沉积坯中疏松形成原因进行了初步探索.研究表明,沉积坯致密度与气体含量、冷却条件等密切相关.一般来说,沉积坯边缘和最后凝固区域致密度相对较低.氮气雾化喷射成形高温合金沉积坯整体致密度可达99%以上,高于氩气雾化沉积高温合金.沉积坯的致密度可通过热等静压等后续工序进一步提高.

Relative density and gas content in spray formed superalloys

One of the most common defects found in spray deposited materials is porosity, which may degrade their mechanical properties especially at elevated temperature, and also affect the secondary working to convert these preforms to the final parts. The size and distribution of pores, the relative density, and gas content of spray formed superalloys and the formation mechanisms of porosity were investigated in this paper. The results indicate that the relative density of deposited superalloys is related closely to the gas content and solidification condition, and the relative densities in edge and finally solidified region are lower. However, the relative density of nitrogen atomized and deposited preform may be greater than 99%, which is higher than that of the argon atomized and deposited preform. Moreover, the relative density of preform can be improved through subsequent processing such as HIP.