多弯道蛇形管浇注法制备半固态A356铝合金浆料

摘要

Using serpentine pipe with multiple curves casting process, semi-solid A356 Al-alloy slurry was prepared.The results show that, at pouring temperatures of 640-680 ℃, when the number of the curves is 3 and their diameters are 20 mm, the semi-solid A356 Al-alloy slurry with shape factor of 0.72-0.85 and grain diameter of 55-75 μm can be prepared. When the number of the curves is 5 and their diameters are 20 mm, the semi-solid A356 Al-alloy slurry with shape factor of 0.86-0.92 and grain diameter of 44-58 μm can be prepared. When the number of the curves is 5 and their diameters are 25 mm, the semi-solid A356 Al-alloy slurry with shape factor of 0.76-0.90 and grain diameter of 48-68 μm can be prepared. With increasing the number of the curves or decreasing their diameters, the morphology and size of the primary α(Al) grains will be improved. The alloy melt has the effect of“self-stirring” in the serpentine curve,which can make the primary nuclei gradually evolve into spherical and near-spherical grains.%采用多弯道蛇形管浇注技术制备半固态A356铝合金浆料.结果表明:在浇注温度为640～680 ℃的条件下,当弯道数量为3且直径为20 mm时,可获得形状因子F为0.72～0.85和晶粒直径D为55～75 μm的半固态浆料;当弯道数量为5且直径为20 mm时,可获得形状因子F为0.86～0.92和晶粒直径D为44～58 μm的半固态浆料;当弯道数量为5且直径为25 mm时,可获得形状因子F为0.76～0.90和晶粒直径D为48～68 μm的半固态浆料.弯道数量增加或弯道直径减小,可以改善初生α(Al)晶粒的形貌和尺寸.弯道内的合金熔体具有"自搅拌"的作用,可使初生晶核逐渐演变为球形或近球形晶粒.