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对铸态Al-Si合金在-196℃进行深冷处理,研究了深冷时间和深冷步数对Al-Si合金的微观组织、布氏硬度和拉伸性能的影响。结果表明:深冷处理可以促进析出细小的Si相;随着深冷时间的增加,导致(200)面衍射峰值先升高后降低;随着深冷时间的增加(0~12 h),硬度逐渐增大,12 h达到最大值,12~24 h逐渐下降并且24 h后趋于稳定,随着深冷步数的增加,硬度也逐渐增大;深冷处理12 h后Al-Si合金的抗拉强度和伸长率分别达到176 MPa和10%。通过指数拟合法建立了深冷时间与硬度的关系方程。
The as-cast Al-Si alloy was cryogenically treated at -196 ℃. The effects of cryogenic time and cryogenic number of steps on microstructure, Brinell hardness and tensile properties of Al-Si alloy were studied. The results show that: the cryogenic treatment can promote the precipitation of small Si phase; with the increase of cryogenic time, the (200) diffraction peak first increases and then decreases; with the increase of cryogenic time (0-12 h), the hardness gradually increases And reached the maximum at 12 h, then gradually decreased at 12-24 h and stabilized at 24 h. With the increase of cryogenic steps, the hardness increased gradually. The tensile strength of Al-Si alloy after cryogenic treatment for 12 h The strength and elongation reach 176 MPa and 10% respectively. The relationship between cryogenic time and hardness was established by exponential fitting method.