热控凝固工艺对薄壁变截面铸件凝固组织和力学性能的影响  

Effect of a Thermally Controlled Solidification Process on the Solidification Microstructure and Mechanical Properties of Thin Wall Castings with Variable Sections

作　　者：郝新 孙裁云 郭敏[1] 介子奇 杨敏[1] 刘鼎元 张军[1] HAO Xin;SUN Caiyun;GUO Min;JIE Ziqi;YANG Min;LIU Dingyuan;ZHANG Jun(State Key Laboratory of Solidification Processing,Northwestern Polytechnical University,Xi'an 710072,China;Aecc South Industry Co.,Ltd.,Zhuzhou 412002,China;School of Materials Science and Chemical Engineering,Xi'an Technological University,Xi'an 710021,China)

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 [2]中国航发南方工业有限公司,湖南株洲412002 [3]西安工业大学材料与化工学院,陕西西安710021

出　　处：《铸造技术》2024年第3期270-278,共9页Foundry Technology

基　　金：国家自然科学基金(52031012,51904218)。

摘　　要：先进航空发动机用机匣等高温合金构件不断向结构复杂化和薄壁轻量化发展,易导致充型困难、组织不均匀和凝固缺陷等问题,对该类铸件的精密铸造技术和工艺控制提出了新的挑战。针对上述问题,文中比较了常规铸造工艺与热控凝固工艺下K4169合金薄壁变截面特征件的充型情况、缩松、组织以及力学性能,并对热控凝固工艺参数进行了探索。结果表明,在常规铸造工艺下,特征件薄壁部位的充型率仅为26%,变截面部位出现了缩松。采用浇注温度为1360℃的热控凝固工艺可以使铸件薄壁部位的充型面积提高226%,显著减少铸件中的缩松,获得了细小的晶粒组织,平均晶粒尺寸为624μm,二次枝晶间距为116μm,Laves相的数量相对较少。同时,由于低浇注温度的热控凝固工艺有效实现了凝固组织细化和缺陷控制,合金在700℃条件下的抗拉强度提高了7%,伸长率由6%提高至8%。Advanced aeroengines and other high-temperature alloy components are constantly evolving towards more complex structures and thin-walled lightweight designs,potentially resulting in issues such as challenging casting,non-uniform microstructures,and solidification defects.These issues pose new challenges for precision casting techniques and process control in the manufacturing of such castings.In this regard,the filling ability,shrinkage,microstructure and mechanical properties of K4169 castings with thin walls and variable cross-sections were compared between conventional casting and thermally controlled solidification methods.The results show that under conventional casting,the filling percentage of the thin-walled part casting is only 26%,and porosity is found in the variable cross-section part.Thermally controlled solidification at a pouring temperature of 1360℃can increase the filling percentage by 226%,significantly reducing the shrinkage in the casting.A fine grain structure with an average grain size of 624μm and secondary dendrite spacing of 116μm is obtained during casting,where the amount of Laves phase is relatively small.Moreover,thermally controlled solidification at a low pouring temperature effectively achieves refinement of the solidification microstructure and defect control,the tensile strength of the alloy increases by 7%,and the elongation increases from 6%to 8%at 700℃.

关 键 词：K4169高温合金 热控凝固工艺 薄壁变截面铸件 充型能力 凝固组织 力学性能 

分 类 号：TG132.3[一般工业技术—材料科学与工程]