Research on the Preparation of Yttrium Sol-Yttria Shell for TiAl Alloy Investment Casting

doi:10.3969/j.issn.1001-1935.2026.03.008

Abstract

Abstract: This study systematically investigates the influence of powder-to-liquid ratio on slurry viscosity and coating performance in a yttrium sol-Y₂O₃ mold system while elucidating the mechanism through which calcination temperature affects mold strength.The comprehensive properties of the shell mold were validated through TiAl alloy blade casting trials.Results demonstrate that slurry viscosity increases exponentially with powder-to-liquid ratios ranging from 3.0 to 4.4,exhibiting three characteristic stages:slow growth (3.0-3.5),accelerated growth (3.5-4.0),and dramatic surge (>4.0),attributable to the evolving proportion between flocculated clusters and free liquid phase.Slurries with powder-to-liquid ratios of 3.2-3.8 achieve optimal balance between high solid content and coating performance,forming uniform and dense face coats.When calcination temperature reaches 1150℃,the mold attains a peak flexural strength of 9.2 MPa (representing a 48.4% enhancement compared to 950 ℃)due to reduced porosity and formation of crystalline bridges between Y₂O₃ particles.Centrifugally cast Ti-48Al-2Nb-2Cr alloy blades exhibited complete mold filling with merely 5 μm interfacial reaction layer and absence of burn-on or inclusion defects.This research provides a high-performance shell mold solution with significant engineering implications for precision casting of TiAl alloys.

Key words: TiAl alloy, Precision casting, Yttria shell, Powder-to-liquid ratio, Sintering temperature, Interfacial reaction

摘要： 为了优化TiAl合金精密铸造用Y₂O₃溶胶结合Y₂O₃型壳的制备工艺,以电熔Y₂O₃粉、Y₂O₃溶胶、莫来石粉和硅溶胶等为原料,通过配制面层浆料、涂挂撒砂、干燥及高温焙烧的工艺流程制备型壳。系统研究了电熔Y₂O₃粉与Y₂O₃溶胶的质量比(简称“粉液比”,为3.0~4.4,间隔0.1)对浆料黏度与涂挂性的影响规律,以及焙烧温度(950~1 150 ℃)对型壳强度的作用机制,并通过TiAl合金叶片浇注验证了型壳的综合性能。结果表明:浆料的黏度和涂挂性随粉液比的增大而增加,但当粉液比≥4.0时,浆料的流动性显著恶化,已无法满足熔模精密铸造的工艺要求;粉液比3.2~3.8的浆料兼具高固含量与良好涂挂性,可形成均匀致密的面层;焙烧温度升至1 150℃时,型壳抗弯强度达9.2 MPa(较950℃提升48.4%),这源于孔隙率降低及Y₂O₃颗粒间晶态桥的形成;离心浇注的Ti-48Al-2Nb-2Cr合金叶片铸件充型完整,界面反应层仅5 μm,且无黏砂、夹杂缺陷。

关键词: TiAl合金, 精密铸造, 氧化钇型壳, 粉液比, 焙烧温度, 界面反应

CLC Number:

TG146.2

HUANG Hong, HU Haitao, GUO jian, DING Xianfei, NAN Hai, JIN Haipeng, YE Lei. Research on the Preparation of Yttrium Sol-Yttria Shell for TiAl Alloy Investment Casting[J]. Refractories, 2026, 60(3): 227-231.

黄宏, 胡海涛, 郭键, 丁贤飞, 南海, 金海鹏, 叶雷. TiAl合金铸造用Y₂O₃型壳的制备及性能研究[J]. 耐火材料, 2026, 60(3): 227-231.

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URL: http://www.nhcl.cn/EN/10.3969/j.issn.1001-1935.2026.03.008

http://www.nhcl.cn/EN/Y2026/V60/I3/227

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