翻譯共八頁(yè) 英翻中
Heat transfer and solidification behaviour of modified A357 alloy
Al–Si alloys are subjected to melt treatment like modification to improve their mechanical properties. Non-destructive technique like thermalanalysis is generally used to assess the effectiveness of melt treatment. In the present study, the behaviour of the melt treated Al–7Si–Mg alloy(A357) during solidification with or without chilling was investigated using thermal analysis. Thermal analysis and heat transfer parameters weredetermined. Thermal analysis parameters were affected significantly by modification and chilling. Modification treatment resulted in the increaseof cooling rate, heat evolved, casting/mould interfacial heat flux and eutectic growth velocity. A theoretical model based on undercooling fromthe equilibrium temperature during eutectic solidification was used to predict growth velocities and eutectic grain size. The eutectic grain sizesestimated using the model and those measured from casting microstructures were found to be in good agreement.

Al-Si合金進(jìn)行熔體處理，如變質(zhì)以改善其力學(xué)性能。非破壞性的技術(shù)，像熱分析通常被用來(lái)評(píng)估熔體處理的有效性。在本研究中，進(jìn)行熔體處理的Al-7Si-Mg合金(A357)采用熱分析研究其在凝固過(guò)程中有無(wú)冷卻行為。熱分析和熱傳輸參數(shù)是確定的。變質(zhì)和冷卻對(duì)熱分析參數(shù)有顯著影響。變質(zhì)處理導(dǎo)致冷卻速率、放熱量、鑄件/鑄型界面熱通量和共晶生長(zhǎng)速率增加?；谶^(guò)冷度的理論模型，共晶凝固期間的平衡溫度被用來(lái)預(yù)測(cè)增長(zhǎng)速度和共晶晶粒尺寸。用這種模型估計(jì)的共晶晶粒尺寸與用鑄件顯微結(jié)構(gòu)測(cè)量的具有很好的一致性。