K417G合金γ+γ′共晶初熔特性及影响因素研究

Study on the Initial Melting Characteristics of γ+γ′ Eutectics in K417G Alloy and Influencing Factors

采用水淬法测定出铸态及采用不同温度阶段处理后的K417G合金γ＋γ′共晶相的初始熔化温度,对铸态合金及水淬处理后的合金的微观组织采用扫描电镜进行观察,确定出阶段热处理对合金中γ＋γ′共晶相的初始熔化温度的影响.研究结果表明：铸态K417G合金中的γ＋γ′共晶相主要由细小的γ＋γ′共晶组织和粗大的γ′相组成,在共晶相的前沿存在少量的硼化物共晶组织.铸态K417G合金中的γ＋γ ′共晶组织的熔化主要发生在共晶相的前沿,熔化后出现大量的白色组织相.电子探针对熔化区的分析表明,熔化后形成的激冷组织主要为γ＋γ′共晶,熔化区主要富集B、Mo和Cr元素.铸态合金中的γ＋γ′共晶的初熔温度为1 220～1 230℃,而经1 090℃、1 100℃和1 110℃阶段处理10h后合金中的γ＋γ′共晶的初熔温度升高至1 280～1 290℃.

Abstract： The initial melting temperatures of γ＋γ ′ eutectics in as-cast and in heat treated K 417G alloy at different temperatures were determined by water quenching method. The microstructures of as-cast and heat treated alloys were then observed by scanning electron microscopy to determine the effect of heat treatment on the initial melting temperatures of γ＋γ ′ eutectics. The results show that the γ＋γ ′ eutectics is composed of small γ＋γ ′ eutectics and big ones mainly, and there is a few boride phase near the eutectic. The initial melting of γ＋γ ′ eutectics occurred mainly at their edge and large white phase appeared after melting. Electron microprobe analysis shows that the quenching structure formed in melting zone was γ＋γ ′ eutectic phase mainly, and B, Mo and Cr elements enriched in these melting zone. The initial melting temperature of γ＋γ ′ eutectics in as-cast alloys is from 1 220 ℃ to 1 230 ~C. After holding the sample at 1090 ℃, 1 100 ~℃ and 1 110 ℃ for 10 h, the initial melting temperature of γ＋γ ′ eutectics increased to 1280-1 290 ℃.