(西北工業(yè)大學(xué) 凝固技術(shù)國家重點(diǎn)實(shí)驗(yàn)室，西安 710072)
摘 要: 采用直徑為4 mm和7 mm的試樣對(duì)Al-4%Cu(質(zhì)量分?jǐn)?shù)，下同)合金進(jìn)行定向凝固實(shí)驗(yàn)。研究表明：小直徑試樣溫度梯度更高,但溫度梯度變化幅度并未與試樣直徑比成線性比例。試樣直徑較小，胞/枝晶間距相應(yīng)較小。獲得直徑為4 mm和7 mm試樣一次枝晶間距與生長速率的關(guān)系，一次枝晶間距和生長速率、溫度梯度的變化關(guān)系，且與理論值相符合；一次枝晶間距實(shí)驗(yàn)結(jié)果與TRIVEDI模型符合較好。
關(guān)鍵字: Al-Cu合金；定向凝固；試樣直徑；一次枝晶間距；理論模型；溫度梯度
（State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China）
Abstract:Directional solidification experiment was carried out on Al-4%Cu(mass fraction) alloy with sample diameters of 4 mm and 7 mm. The results show that the sample with small diameter gets higher thermal gradient, the variation range of temperature gradient is not direct proportional to the ratio of diameters. Thin samples correspond to the smaller cellular and dendrite arm spacing. The variation of primary dendrite arm spacing for 4 mm and 7 mm sample in diameter with growth velocity and the relationship of primary dendrite arm spacing with growing velocity and temperature gradient are obtained. Both relationships agree with the theoretical model. The experimental result fit well with TRIVEDI model.
Key words: Al-Cu alloy; directional solidification; sample diameter; primary dendrite arm spacing; theoretical model; thermal gradient
