Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Fei Li; Hongjun Ni; Lixiang Yang; Yi Jiang; Donghong Wang; Baode Sun

doi:10.3390/ma12040606

Investigation of Fused Alumina Based-Mold Facecoats for DZ22B Directionally Solidified Blades

Materials (Basel). 2019 Feb 18;12(4):606. doi: 10.3390/ma12040606.

Authors

Fei Li^{1

2}, Hongjun Ni³, Lixiang Yang⁴, Yi Jiang⁵, Donghong Wang⁶, Baode Sun⁷

Affiliations

¹ Shanghai Key Laboratory for High Temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. lifei74@sjtu.edu.cn.
² State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China. lifei74@sjtu.edu.cn.
³ School of Mechanical Engineering, Nantong University, Nantong 226019, China. ni.hj@ntu.edu.cn.
⁴ Shanghai Key Laboratory for High Temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. yanglixiang@sjtu.edu.cn.
⁵ Shanghai Key Laboratory for High Temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. MarzPicture@sjtu.edu.cn.
⁶ Shanghai Key Laboratory for High Temperature Materials and Precision Forming, Shanghai Jiao Tong University, Shanghai 200240, China. wangdh2009@sjtu.edu.cn.
⁷ State Key Laboratory of Metal Matrix Composites, Shanghai Jiao Tong University, Shanghai 200240, China. bdsun@sjtu.edu.cn.

Abstract

The interaction between alloy melt and mold facecoats is the main factor affecting the surface quality of investment casting nickel-based superalloys. An investigation was undertaken to develop suitable refractories as facecoat materials for the directionally solidified blades of DZ22B nickel-based superalloys in order to avoid a sand-burning defect. The wettability and interface reactions between alloy melt and various facecoats were studied by using a sessile drop experiment and the real investment casting method, respectively. The results show that by adding Cr₂O₃ powder with the amounts of 2 wt.%, 5 wt.% and 10 wt.% in the fused alumina-based facecoats, the wetting angles between the alloy melt and facecoats decreased from 105.40° to 100.37°, 99.96° and 98.11°, respectively, while the sand-burning defect on the casting blade surfaces still formed during the process of directional solidification. However, by adding h-BN powder in the fused alumina-based facecoats, the wetting angles between the alloy melt and facecoats dramatically increased, the sand-burning defect on the casting blade surfaces was effectively inhibited and a metallic luster on the directionally solidified blades could be obviously observed. In this study, the suitable composition of mold facecoats for the investment casting of blades is 2 wt.% h-BN added fused alumina.

Keywords: DZ22B nickel based superalloy; directionally solidified blade; investment casting; mold facecoat; sand burning.