As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray ...As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively. The results show that rod-like Al4Ce phase is formed in AZ91D alloy containing certain Ce content and as-cast microstructures are refined. AZ91D-0.7%Ce alloy has good grain refinement effect. The addition of Ce can reduce the corrosion rate and corrosion current density of AZ91D alloy and those of AZ91D-0.1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and 2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.展开更多
The influences of P and rare earth （RE） complex modifier on the microstructure and mechanical properties of hypereutectic Al-21%Si alloy were studied. The ingots were made by metal mold casting and the proportion of...The influences of P and rare earth （RE） complex modifier on the microstructure and mechanical properties of hypereutectic Al-21%Si alloy were studied. The ingots were made by metal mold casting and the proportion of Ce＋P ingredient was different. The result showed that the size of grains could be refined obviously by the Ce＋P modifier and the effect of phosphorus was more intensive The primary silicon crystal was refined, while the needle-like eutectic silicon was turned fibrous or short. The alloy mechanical prop- erties had the best performance when 0.08% P and 0.6% Ce were added. The modification of primary silicon grains mainly depended on the heterogeneous nucleation mechanism, and the metamorphic mechanism of eutectic silicon was explained by adsorbing-twirming theory. The strengthening mechanism of experimental alloy was also discussed. The σb, 20 ℃ increases from 236.2 to 287.6 MPa and σb, 300 ℃ increases from 142.5 to 210 MPa.展开更多
基金This work was supported by the National Natural Science Foundation of China(No.50271054)the State Educational Ministry for Scientific Research Foundation for the Returned Overseas Chinese Scholars.
文摘As-cast and corrosive microstructures of AZ91D alloy containing various Ce contents were observed by optical microscope (OM). The phase compositions of the alloys before and after the corrosion were analyzed by X-ray diffraction (XRD). Meanwhile, the corrosion resistance of the alloys was tested by weight loss and potentiodynamic polarization curve methods respectively. The results show that rod-like Al4Ce phase is formed in AZ91D alloy containing certain Ce content and as-cast microstructures are refined. AZ91D-0.7%Ce alloy has good grain refinement effect. The addition of Ce can reduce the corrosion rate and corrosion current density of AZ91D alloy and those of AZ91D-0.1%Ce alloy reach the minimum, which are 0.35mg/(cm2·d) and 2.761μA/cm2 with 75% and 86% reduction, respectively. The increasing volume fraction and reticular degree of β phase can improve the corrosion resistance of the alloys.
基金supported by Advancing Front Science of Henan Province(092300410049)
文摘The influences of P and rare earth （RE） complex modifier on the microstructure and mechanical properties of hypereutectic Al-21%Si alloy were studied. The ingots were made by metal mold casting and the proportion of Ce＋P ingredient was different. The result showed that the size of grains could be refined obviously by the Ce＋P modifier and the effect of phosphorus was more intensive The primary silicon crystal was refined, while the needle-like eutectic silicon was turned fibrous or short. The alloy mechanical prop- erties had the best performance when 0.08% P and 0.6% Ce were added. The modification of primary silicon grains mainly depended on the heterogeneous nucleation mechanism, and the metamorphic mechanism of eutectic silicon was explained by adsorbing-twirming theory. The strengthening mechanism of experimental alloy was also discussed. The σb, 20 ℃ increases from 236.2 to 287.6 MPa and σb, 300 ℃ increases from 142.5 to 210 MPa.
