The Multi-diffusion Of Al-zr-cr-la Alloy Phase Formation And Its Role In Research

Conventional dispersoids of aluminum alloys have been difficult to satistify the property and cost requirements, so it's necessary to search for new and cheap aluminide dispersoids. By using rapid solidification, the solid solubility of elements will increase greatly and form supersaturated solid solution in aluminum,then precipitates high volume fraction dispersoids under high temperature condition,but there exits the problem of high cost and complex processes with preparing alloys by this method. In this paper, preparing alloys with multi-alloying by mean of ingot metallurgy, in order to attain new and desired aluminide dispersoids.In this paper, the formation and the effects of Al-Zr-Cr-La dispersoid in aluminum alloy have been investigated, by methods of optical microscopic analysis,SEM analysis, X-ray diffraction analysis, tensile mechanical properties test and hardness test.Combined additions of Cr and La in aluminum can form Al₂₀Cr₂La dispersoid; Combined additions of Zr, Cr and La can also form Al₂₀Cr₂La structure type dispersoid, with Zr being dissolved. Compared wih Al₂₀Cr₂La dispersoid, the capability of inhibiting recrystalization and strengthening effect of Al-Zr-Cr-La dispersoid in aluminum are improved.Silimar to effects in pure aluminum, Al₂₀Cr₂La dispersoid and Al-Zr-Cr-La dispersoid also strengthen Al-Mg alloys and inhibit deformed Al-Mg alloys' recrystalization. Compared with Al₂₀Cr₂La dispersoid, the capability of inhibiting recrystalization and strengthening effect of Al-Zr-Cr-La dispersoid in Al-Mg alloys are improved.Combined additions of 0.16%Zr, 0.15%Cr and 0.13%La in cast Al-Cu alloys can improve as-cast, peak-aged,age-annealed hardness and peak-aged tensile strength.The constituents phases in grain boundary and interdendritic increase with combined additions of Zr,Cr and La in cast Al-Cu alloys. Reducing La addition properly, less soluble constituents phases will decrease, and tensile strength is improved while plasticity is kept.Combined additions of Zr, Cr and La in cast Al-Cu-Si alloys can improve peak-aged,age-annealed hardness and peak-aged tensile strength. There exits needle-like phase in alloy structure with only La addition, which lead to the decline of hardness and tensile strength. Combined additions of Zr, Cr and La in cast Al-Cu-Si alloys reduce the needle-like phase and diminish its size; then improve the tensile strength and kept plasticity of alloys.