(1. 西北工業(yè)大學 凝固技術國家重點實驗室，西安 710072；
2. 西北工業(yè)大學 材料科學與工程學院，西安 710072)
摘 要: 基于微觀相場動力學模型，以Ni75Al25−xVx合金為對象，研究時效溫度變化對沉淀相競爭生長機制及筏狀組織形成的影響。結果表明：相的生長和粗化存在各向異性和競爭機制；當具有生長各相異性的DO22相數(shù)量較少、尺寸較大時，易形成單一方向排布的組織，從而促使具有生長各向同性的L12相也沿著特定的方向生長，最終形成具有高度擇向生長的“筏狀”組織，且隨著時效溫度的降低，沉淀相提前析出；若L12相先析出，時效溫度越低，DO22相越多，組織筏化越不明顯；若DO22先析出，時效溫度越低，DO22相越少，組織筏狀越顯著。
關鍵字: Ni75Al25−xVx合金；微觀相場；筏化；時效溫度
ageing temperature on raft in Ni-Al-V alloys
（1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China;
2. School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Based on the microscopic phase-field kinetic model and Ni75Al25−xVx alloy, the influences of ageing temperature on the competitive growth mechanism and raft structure were studied. The results show that the growth and coarsening of phase is a competitive process. It will form raft structure when the number of DO22 is less and the size is larger, causing L12 phase growing along the same direction. The precipitate phases appear earlier at a low temperature. There is more DO22 grain and not obvious raft structure at lower temperature if L12 phase precipitates first. There is less DO22 grain and obvious raft structure at lower temperature if DO22 phase precipitates first.
Key words: Ni75Al25−xVx alloy; microscopic phase-field; raft; ageing temperature
