Abstract A low-cost, new casting Sr-modified Al-7.5Si-0.8Fe alloy with high-thermal conductivity was prepared into large thin-wall heat-dissipating shells for 5G communication base stations using a traditional high pressure die-casting (HPDC) process and a rheological HPDC (R-HPDC) technique. Their microstructure, tensile property, hardness, thermal conductivity, and corrosion behavior were analyzed. The R-HPDC Al-7.5Si-0.8Fe alloy shows a refined microstructure in terms of α1-Al particles, α2-Al grains, fibrous β-Al5FeSi, and granular eutectic silicons when compared to traditional HPDC alloys. The R-HPDC alloy has a thermal conductivity, elongation-to-failure value, ultimate tensile strength, yield strength, and Vickers hardness of 186 W/(m.K), 12.4 %, 235 MPa, 114 MPa, and 70 HV, respectively. These values are respectively 6 %, 91 %, 22 %, 14 %, and 11 % higher than those reported for conventional HPDC alloys. Moreover, the R-HPDC Al-Si-Fe alloy shows a superior corrosion resistance in comparison to HPDC alloys. This observation is supported by scanning Kelvin probe (SKP) measurements and electrochemical tests. The improved performances arise mostly from the refinement of the iron-rich intermetallics (β-Al5FeSi) and eutectic silicons, the increase in the area proportion of α2-Al grains relative to eutectic silicon, and the reduction in the potential difference between the aluminum matrices and the iron-rich intermetallics.

中文翻译：

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通过新型 R-HPDC 工艺改善新型高导热 Al-Si-Fe 合金的机械、导热和腐蚀性能

摘要 采用传统的高压压铸 (HPDC) 方法制备了一种低成本、新型铸造高导热率的 Sr 改性 Al-7.5Si-0.8Fe 合金，制成了 5G 通信基站用大型薄壁散热壳。 ) 工艺和流变 HPDC (R-HPDC) 技术。分析了它们的微观结构、拉伸性能、硬度、导热性和腐蚀行为。与传统的 HPDC 合金相比，R-HPDC Al-7.5Si-0.8Fe 合金在 α1-Al 颗粒、α2-Al 晶粒、纤维状 β-Al5FeSi 和粒状共晶硅方面显示出精细的微观结构。R-HPDC 合金的热导率、断裂伸长率值、极限抗拉强度、屈服强度和维氏硬度分别为 186 W/(mK)、12.4%、235 MPa、114 MPa 和 70 HV。这些值分别为 6 %、91 %、22 %、14 %、比传统 HPDC 合金报道的高 11%。此外，与 HPDC 合金相比，R-HPDC Al-Si-Fe 合金显示出优异的耐腐蚀性。这种观察得到了扫描开尔文探针 (SKP) 测量和电化学测试的支持。性能的提高主要来自于富铁金属间化合物 (β-Al5FeSi) 和共晶硅的细化，α2-Al 晶粒相对于共晶硅的面积比例增加，以及铝基体之间的电位差减小和富含铁的金属间化合物。