铸造工艺参数和细化剂对K4169高温合金铸态组织的影响 II.枝晶组织及晶粒球化机理  

EFFECTS OF FOUNDRY VARIABLES AND REFINERS ONCAST STRUCTURES OF SUPERALLOY K4169Ⅱ. Dendrite Structures and Granulation Mechanisms

作　　者：熊玉华[1] 李培杰[1] 曾大本[1] 杨爱民[2] 严卫东[2] 刘 林[2] 

机构地区：[1]清华大学机械工程系,北京100084 [2]西北工业大学应用物理系,西安710072

出　　处：《金属学报》2002年第5期534-538,共5页Acta Metallurgica Sinica

基　　金：国家重点基础研究发展规划项目 G2000067202资助

摘　　要：铸造工艺参数和细化剂对K4169合金枝晶组织、元素偏析、夹杂及缩松有明显的影响,浇注温度越低,一次枝晶主轴长度和二次枝晶臂距就越小,在同一浇注温度下,化学法细晶试样的一次枝晶主轴长度较普通铸造试样的短,但二者的二次枝晶臂距没有明显差别,晶粒细化后,合金中主要元素Fe,Cr,Nb,Mo和Ti的偏析减轻,晶粒的形态由树枝晶向细晶组织中的粒状晶转变,对晶粒球化现象做了合理解释,微量细化剂的加入不会在铸件中形成夹杂,不会改变合金的相组成,在高的浇注温度下,细化剂使晶粒细化的同时,也使铸件中的缩松大大减少。The effects of foundry variables and refiners on dendrite structures, micro segregation, inclusion and microporosity of cast superalloy K4169 have been studied. The results indicate that while keeping the other recessing parameters invariant, both the average principal axis length of the primary dendrites (Laxis) and the secondary dendrite arm spacing (SDAS) reduce with decreasing the pouring temperature. At the same pouring temperature, Laxis is shortened with the addition of refiners but the SDAS keeps almost unchanged. Meanwhile, the microsegregation of main elements such as Fe, Cr, Nb, Mo and Ti is alleviated with the decrease in grain size, and the grains have transformed from dendrite to granulation in fine-grained castings. Furthermore, it is found that trace addition of refiners to the melt did not form inclusion and change the phase constitution of the alloy. At high pouring temperature, the amount of microporosity in samples with the addition of refiners can be greatly reduced.

关 键 词：铸造工艺参数 细化剂 K4169高温合金 铸态组织 枝晶组织 晶粒球化机理 

分 类 号：TG132.32[一般工业技术—材料科学与工程] TG27[金属学及工艺—合金]