耦合压力-气体雾化工艺制备微细球形铝合金粉末

Coupled Pressure-Gas Atomization Process for Fine Spherical Aluminium Alloy Powder Production

介绍了一种耦合压力-气体雾化金属粉末制备工艺。在该工艺中,熔体在正压驱动下可以通过出口孔径较小的导流嘴,形成低维度的熔体射流,提高了粉末的细粉收得率。采用该工艺制备了AlSi10Mg合金粉末,雾化气压(2.0±0.3) MPa,在熔体上方施加正压(0.3±0.05)×10^5 Pa,选取导流嘴出口孔径2 mm,粒径53μm以下粉末的收得率达到40%;与市场上现有的国产及进口AlSi10Mg合金粉末相比,该工艺制备的粉末球形度较高,表面光滑,卫星粉较少;以该工艺生产的AlSi10Mg合金粉末为原料,制备的选取激光熔化成型件的室温拉伸性能优于进口粉末。该工艺能够解决高粘性熔体导流时可能发生的导流嘴堵塞问题。采用该工艺制备了含硅量18%~20%(质量分数)、含铁量5%~6%的改进2009铝合金粉末,在熔体上方施加正压驱动(0.4±0.05)×10^5 Pa,高粘性的铝合金熔体在熔化温度850℃时可以顺利通过出口孔径为4~2 mm的导流嘴;采用雾化气压(2.0±0.3) MPa,随着导流嘴出口孔径的减小,粉末的收得率(100μm以下)增加,粒度分布变窄,体积中值粒径降低;选取导流嘴出口孔径2 mm,粉末的收得率(100μm以下)达到80%,体积中值粒径(d50,3)约为55μm。

Coupled pressure-gas atomization(PGA) technique was introduced for metal powder production. In the PGA process, the melt could be pressurized to go through a melt-guiding-nozzle(MGN) with a very thin inner-diameter, thereby forming a very thin melt jet. By this way, a high yield of fine metal powder could be obtained. AlSi10Mg alloy powder was produced by the PGA process, whereby a MGN with an inner-diameter of 2 mm, together with a gas atomization pressure of(2.0±0.3) MPa and an over-pressure of(0.3±0.05)×105 Pa on the melt, was employed. In this case, a powder yield of >40% could be reached for a particle size range of <53 μm;compared with those from domestic market and imported from abroad, the AlSi10Mg alloy powder produced by the PGA process exhibited higher sphericity, smooth surface and fewer satellites;the specimens made from such powders by selective laser melting process led to tensile properties comparable to that from imported powders. The PGA technique could deal with the clogging problem when a highly viscous melt, i.e. the modified 2009(Mod 2009) Al-alloy melt with 18%~20% Si and 5%~6% Fe, went through a MGN. At a melting temperature of 850 ℃, the viscous melt, driven by an over-pressure of(0.4±0.05)×105 Pa, could go through a MGN with an inner-diameter in a range of 4~2 mm;with a decreasing MGN inner-diameter, the fine powder yield increased, the particle size distribution became narrow, and the volume median diameter decreased. In the case of a MGN with an inner-diameter of 2 mm, the fine powder yield(<100 μm) could reach 80%, and the volume median diameter(d50,3) was about 55 μm.