FGH95與Rene'95合金粉末熱學凝固參數和微觀組織

Comparison of Microstructures and Calculated Solidification Parameters Between FGH95 and Rene' 95 Superalloy Powders

摘要: 大量實驗證明,鑄態組織中二次枝晶臂距主要受冷卻速度或凝固時間的影響。本文對FGH95和Rene’95氬氣霧化的、不同粒度級的粉末顆粒測定了二次枝晶臂距,計算了冷卻速度Ṫ、完成凝的固時間tf、凝固速度R及固—液界面前沿溫度梯度G。結果表明:兩種粉末粒度在-60—+320目范圍內冷卻速度為10³-10⁴℃/s,凝固時間為10^-1—10^-2s。隨著粉末顆粒減小,冷卻速度增加,G/R值增大,粉末顆粒的凝固從以樹枝晶為主的方式逐漸轉變成以胞狀晶為主的方式,用G/R值來判斷凝固組織中的碳化物形態不是唯一因素。

Abstract: Dendritic arms spacings of FGH95 and Rene'95 atomized powder for different mesh size were measured. Cooling rate (Ṫ) > local solidification time(t_f), thermal gradient (G), and growth rate (R) were calculated.It is shown that as local solidification time is 10^-1-10^-2s,cooling rate of two powders inside the range of -60-+320 mesh is 103-104℃/s.The cooling rate and O/R ratio inerease with decreasing particle size and dendrite structure of powder particle correspondly changes into cellular structure.It seems that the morphology of MC carbibe in powder particle does not depend only on O/R ratio.