(1. 長安大學(xué) 材料科學(xué)與工程學(xué)院，西安 710064；
2. 西安賽特思邁鈦業(yè)有限公司，西安 710018；
3. 西北工業(yè)大學(xué) 凝固技術(shù)國家重點實驗室，西安 710072)
摘 要: 基于實驗研究、熱力學(xué)計算與動力學(xué)分析，研究了Ni含量對Co-Al-W基單晶高溫合金凝固特性的影響。結(jié)果表明：無Ni和添加Ni的Co基單晶高溫合金均具有典型的枝晶組織，但Ni的添加增大了合金的一次枝晶間距。同時，Ni的添加增大了Al和W元素的顯微偏析傾向，降低了Ta元素的顯微偏析傾向，但對Ti元素的顯微偏析傾向的影響較小。無Ni合金的枝晶間析出相為初生γ′相和(β+γ′)共晶相，而含Ni合金的枝晶間析出相為初生γ′相，即Ni的添加改變了合金的凝固路徑與鑄態(tài)組織。同時，Ni的添加對Co-Al-W基單晶高溫合金凝固特征溫度的影響不明顯。
關(guān)鍵字: Ni添加量；Co-Al-W基單晶高溫合金；枝晶組織；顯微偏析；凝固路徑；凝固特征溫度
（1. School of Materials Science and Engineering, Chang’an University, Xi’an 710064, China;
2. Xi’an SaiteSimai Titanium Industry Co., Ltd., Xi’an 710018, China;
3. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:The effect of Ni addition on solidification characteristics of Co-Al-W based single crystal superalloy was investigated via experimental, thermodynamical and dynamical analysis. Both Ni-free and adding Ni Co-Al-W based single crystal superalloy has the typical dendritic microstructure, and Ni addition increases the primary dendritic arm spacing of single crystal superalloy. Meanwhile, with increasing Ni content, the microsegregation degrees of Al and W elements increase, the microsegregation degree of Ta element decreases, while Ni addition has little influence on the microsegregation degree of Ti element. Moreover, the interdendritic precipitations of Ni-free single crystal superalloy are primary γ′ phase and (β+γ′) eutectic phase, while the interdendritic precipitation of Ni single crystal superalloy is primary γ′ phase, which indicates that Ni addition changes the solidification path and as-cast microstructure of single crystal superalloy. In addition, the influence of Ni addition on solidification characteristic temperatures of Co-Al-W based single crystal superalloy is not obvious.
Key words: Ni addition amount; Co-Al-W based single crystal superalloy; dendritic microstructure; microsegregation behavior; solidification path; solidification characteristic temperatures
