试样截面尺寸变化对高温合金DZ125定向凝固组织的影响  

Effect of Variation in Cross-Section Size of Samples on Directional Solidification Microstructure of DZ125 Superalloy

作　　者：陈波[1] 刘林[1] 张卫国[1] 傅恒志[1] 

机构地区：[1]西北工业大学凝固技术国家重点实验室,陕西西安710072

出　　处：《铸造》2009年第6期589-592,共4页Foundry

摘　　要：采用截面变化的DZ125高温合金试样进行液态金属冷却定向凝固,抽拉速率为25μm/s、50μm/s、100μm/s和500μm/s,获得了截面变化前后的稳定组织以及截面变化区的组织演变。结果表明,当凝固顺序由大截面向小截面时,一次枝晶间距变窄,抽拉速率为500μm/s时,枝晶生长方向发生偏转。随着试样比表面积的增大,一次枝晶间距减小。由于截面的变化,组织的演化是一个渐变的过程,不同的冷却速率和凝固顺序都影响着组织的演化过程。With directional solidification of liquid metal cooling, the stable microstructure of the samples with different size of the cross section and the microstructure evolution of section-changed region were obtained at the withdrawal rate of 25 μm/s, 50 μm/s, 100 μm/s and 500 μm/s, respectively for the DZ125 superalloy. It is concluded that the primary dendrite μm spacing （PDAS） narrows down with the cross-section size decrease. The deflection of dendrite growth direction occurs at the rate of 500 μm/s. With the increase of specific surface area of the samples, the PDAS reduces. Due to the variation in cross-section size, the evolution of microstructure gradually occurs. Both cooling rate and solidification sequence impact on structure evolution process.

关 键 词：高温合金 定向凝固 截面尺寸变化 抽拉速率 

分 类 号：TG146.15[一般工业技术—材料科学与工程]