Weiguo Jiang
材料科学技术（英文）
A novel water-soluble core material composed of polyethylene glycol, sodium chloride, mica powder and plasticizer was prepared. The compressive strength, bend strength, hygroscopic coefficient and the material solubility in water were investigated. The results show that the compressive yield strength of the soluble core can reach 1 MPa and the highest compressive strength can reach 4 MPa, the bend strength is as high as 6.65 MPa, the hygroscopic coefficient is lower than 0.22%/month and the solubility of suitable core material is 35.7-55.75 g/(min·m2). The wax pattern with undercuts was prepared successfully by using the novel water-soluble core material.
关键词:
Investment cast
,
Core materials
,
Mechanical property
,
Microstructure
Weiguo Jiang
材料科学技术（英文）
Four castings with different modulus have been designed to simulate different thickness sections of a turbine blade during casting process. The microstructure has been observed by optical microscopy (OM) and scanning electron microscopy (SEM). The micro-segregation was tested by energy dispersive spectroscopy (EDS) and the macro-segregation was analyzed by using Metalscan 2500 spectrometers. The experimental results show that the microstructure of casting is affected by modulus apparently. The smaller the modulus, the finer the microstructure. The average grain size of castings with modulus of 0.29, 1.57, 3.16 and 5.0 mm is 0.3, 1.5, 2.7 and 4.3 mm, and the volume fraction of eutectic is 0, 0.1%, 0.2% and 1.0%, respectively. The micro/macro segregation is affected by the modulus apparently. The smaller the modulus, the lower the segregation level. When the modulus of casting increases, the content of Al increases, while the content of W, Cr and Mo decreases both in inner grain and near grain boundary. The content of Al and Mo in inner grain is higher than that near grain boundary, while the content of Cr and W in inner grain is lower than that near grain boundary.
关键词:
Superalloy
