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 i...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·m 2）.The wax pattern with undercuts was prepared successfully by using the novel water-soluble core material.展开更多
A more complex structural component with small size and very thin walls and blades used for advanced aircraft engine was fabricated well by induction skull melting and centrifugal investment casting with a proper cera...A more complex structural component with small size and very thin walls and blades used for advanced aircraft engine was fabricated well by induction skull melting and centrifugal investment casting with a proper ceramic mold. The tensile elongation and ultimate strength of the hot isostatically pressed (HIPped) Ti 46.5Al 2.5V 1Cr (mole fraction, %) casting alloys are up to 2.5% and 645?MPa at room temperature, and 31% and 593?MPa at 800?℃. The fracture roughness at room temperature is up to 28?MPa·m 1/2 . The endurance tensile strength at 800?℃ for 150?h, is higher than 200?MPa. The high cycle rotary bending fatigue strengths for 1×10 7 cycles at room temperature and 800?℃ are 412?MPa and 270?MPa, respectively.展开更多
In this work, two kinds of binders, Ammonium Zirconium Carbonate(AZC) and Ammonium Metatungstate(AMT) hydrate, and three kinds of powders(ZrO 2, Al2O3 and Y2O3) were mixed to fabricate six kinds of face coating system...In this work, two kinds of binders, Ammonium Zirconium Carbonate(AZC) and Ammonium Metatungstate(AMT) hydrate, and three kinds of powders(ZrO 2, Al2O3 and Y2O3) were mixed to fabricate six kinds of face coating systems. The thermal behaviors of the AZC and AMT dried binders were investigated by TG-DTA, and the phase transformation of the two binders was determined by XRD. Monoclinic ZrO 2 phase was formed from AZC at 620 °C and WO3 at 700 °C, and the phase transformation was completed at lower than 1000 °C in both binders, and therefore, the sintering temperature for the molds was selected at 950 °C. The interaction between the ceramic molds with different face coatings and the Ti-48Al-2Cr-2Nb alloy during investment casting was studied. Results showed no α-case reaction in the TiA l-mold reaction, and the AMT + Y2O3 face coating appeared to be the best choice for investment casting of TiA l alloys under the experimental conditions.展开更多
文摘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·m 2）.The wax pattern with undercuts was prepared successfully by using the novel water-soluble core material.
文摘A more complex structural component with small size and very thin walls and blades used for advanced aircraft engine was fabricated well by induction skull melting and centrifugal investment casting with a proper ceramic mold. The tensile elongation and ultimate strength of the hot isostatically pressed (HIPped) Ti 46.5Al 2.5V 1Cr (mole fraction, %) casting alloys are up to 2.5% and 645?MPa at room temperature, and 31% and 593?MPa at 800?℃. The fracture roughness at room temperature is up to 28?MPa·m 1/2 . The endurance tensile strength at 800?℃ for 150?h, is higher than 200?MPa. The high cycle rotary bending fatigue strengths for 1×10 7 cycles at room temperature and 800?℃ are 412?MPa and 270?MPa, respectively.
基金financially supported by the National Natural Science Foundation of China(Nos.51001040 and 51371064)
文摘In this work, two kinds of binders, Ammonium Zirconium Carbonate(AZC) and Ammonium Metatungstate(AMT) hydrate, and three kinds of powders(ZrO 2, Al2O3 and Y2O3) were mixed to fabricate six kinds of face coating systems. The thermal behaviors of the AZC and AMT dried binders were investigated by TG-DTA, and the phase transformation of the two binders was determined by XRD. Monoclinic ZrO 2 phase was formed from AZC at 620 °C and WO3 at 700 °C, and the phase transformation was completed at lower than 1000 °C in both binders, and therefore, the sintering temperature for the molds was selected at 950 °C. The interaction between the ceramic molds with different face coatings and the Ti-48Al-2Cr-2Nb alloy during investment casting was studied. Results showed no α-case reaction in the TiA l-mold reaction, and the AMT + Y2O3 face coating appeared to be the best choice for investment casting of TiA l alloys under the experimental conditions.
