新型细化剂对K4169高温合金晶粒组织的影响

Effects of New Refiners on Grain Structures of Cast Superalloy K4169

研究了新型细化剂对 K41 6 9高温合金晶粒组织的影响 ,提出了晶粒细化的机理。结果表明 :加入新型细化剂不仅使凝固后基体的晶粒尺寸减小 ,而且可提高铸件断面等轴晶的比例。在通常浇注温度 1 40 0℃下 ,加入由两种三元金属间化合物所制成的复合细化剂 ,对合金熔体进行、不进行均匀化处理时 ,可使圆柱锭的晶粒分别细化至 ASTM1 .7级和 ASTM3 .2级 ;断面等轴晶的比例从 5 6 %分别提高到 96 %和 99%。研究还发现细化剂加入工艺如加入单一或复合细化剂、细化剂的种类和粒度等的不同会产生不同的细化效果 ,本文对这些现象进行了解释。

Effects of new refiners on grain structures of cast superalloy K4169 have been investigated. It is shown that the addition of new refiners could lead to reduction in average equiaxed grain size and increase in the proportion of equiaxed grains at cross-section. Under the same conditions of adding mixed refiner consisting of two ternary intermetallic compounds and pouring at a conventional pouring temperature of 1 400℃, the average equiaxed grains (r) could be refined to the order of ASTM 1.7, the proportion of equiaxed grains at cross-section (p) could be improved from 56% to 96% if the melt was homogeneously treated. If the melt was not homogeneously treated, r could be refined to 0.115 8 mm, i.e. ASTM 3.2, and p could be improved to 99%. Moreover, grain refinement mechanisms were proposed. Experimental results also indicate that the difference in addition technology of refiner, such as single or mixed refiners, and the difference in the kind and granularity of refiners result in different refining effect.