热处理对Al-Si-Mg-Cr合金微观组织与力学性能及耐腐蚀性能的影响

Effect of Heat Treatment on Microstructure, Mechanical Properties and Corrosion Resistance of Al-Si-Mg-Cr Alloy

摘要:

本文采用真空电磁感应熔炼炉制备了Al-Si-Mg-Cr合金,利用Thermo-calc软件进行热力学模拟，使用SEM、EDS等测试方法，表征了不同热处理状态下Al-Si-Mg-Cr合金微观组织，并测试其力学性能。采用了失重法和电化学法测试其腐蚀性能。结果表明：实验合金主要物相包括初晶α-Al、（α-Al+Si）共晶、Al13Cr4Si4、β-Al（Cr, Fe）Si、富Fe相（β-Al5FeSi和π-AlSiMgFe）。热处理后的实验合金组织均得到细化，共晶组织区域变窄，共晶Si球化，合金中Al13Cr4Si4、β-Al（Cr, Fe）Si相弥散分布。腐蚀测试结果显示：实验合金主要的腐蚀方式为晶间腐蚀，热处理后实验合金共晶区域减小，导致腐蚀通道变窄；提高了合金的耐腐蚀性能。当热处理工艺为535℃ 6h+160 26h时，实验合金微观力学性能及耐腐蚀性最佳。

Abstract:

In this paper, the Al-Si-Mg-Cr alloy was prepared by vacuum electromagnetic induction melting furnace. Thermo-calc software was used for thermodynamic simulation, and SEM, EDS and other test methods were used to characterize the microstructure of Al-Si-Mg-Cr alloy under different heat treatment conditions tissue and test its mechanical properties. The corrosion properties of the experimental alloys were tested by weight loss method and electrochemical method. The results show that the main phases of the experimental alloy include primary α-Al, (α-Al+Si) eutectic, Al13Cr4Si4, β-Al (Cr, Fe) Si, and Fe-rich phases (β-Al5FeSi and π-AlSiMgFe). After heat treatment, the experimental alloy structure was refined, the eutectic area is reduced, the eutectic Si was spheroidized, and the Al13Cr4Si4,β-Al(Cr, Fe)Si phases were dispersed and distributed in the alloy. The corrosion test results show that the main corrosion mode of the experimental alloy is intergranular corrosion. After heat treatment, the eutectic area of the experimental alloy decreases, which leads to the narrowing of the corrosion channel and improves the corrosion resistance of the alloy. When the heat treatment process is 535℃ 6h+160 26h, the micromechanical properties and corrosion resistance of the experimental alloy are the best.