镍基单晶高温合金亚结构细化和偏析研究  

Superfine Dendrite and Microsegregation of NiBase Single Crystal Superalloy

作　　者：杜炜[1,2] 魏朋义[1,2] 李建国[1,2] 傅恒志[1,2] 

机构地区：[1]西北工业大学 [2]北京航空材料研究院

出　　处：《西北工业大学学报》1998年第3期364-367,共4页Journal of Northwestern Polytechnical University

摘　　要：利用高梯度定向凝固技术（ＨＧＤＳ）对镍基单晶高温合金亚结构枝晶组织的超细化和显微偏析进行了研究。结果表明，在高的凝固界面温度梯度下，得到具有超细枝晶组织的材料，枝晶偏析的程度和尺度都减小，对均匀化处理和提高材料的性能都有利。The refinement of primary dendrite arm spacing is in general desirable. Our research aims at finding out how far such refinement can be pushed beyond that available with the HRS processing generally employed in industrial production of Nibase single crystal superalloy. With the help of hightemperature gradient directional solidification equipment (HGDS), the microstructure and microsegregation of Nibase single crystal superalloy CMSX-2 solidified at the cooling rates from below 1 K/s to 20 K/s were investigated. The morphologies of γ′ precipitates and γ/γ′ eutectic in the specimens were examined. The results show that, with the increase of the cooling rate, the primary dendrite arm spacing is greatly refined; it can be made to be 49μm, iust one eighth of that possible with HRS processing. The microsegregation increases and then decreases with the increase of cooling rate. In the superfine columnar dendrite, the γ′ precipitates are very fine; the amount of γ/γ′ eutectic is much less and its size is very small.

关 键 词：镍基 单晶 高温合金 显微偏析 亚结构 细化 偏析 

分 类 号：TG132.32[一般工业技术—材料科学与工程]