功率对EIGA制备3D打印用TC4合金粉末特性的影响

与传统的雾化制粉技术不同,电极感应熔炼气体雾化(EIGA)技术是采用预合金棒料为电极,无坩埚感应加热,熔化后直接滴落雾化区被惰性气体雾化的技术.该技术由于在熔炼过程中液态金属与坩埚不接触,有效地减少了钛合金粉末中的夹杂物,改善了合金粉末的质量.本文利用自主设计制造的EIGA制粉设备,采用激光粒度分析仪、扫描电镜(SEM)、X射线衍射仪(XRD)等分析手段,研究了不同功率参数对雾化制备TC4合金粉末的粒度分布、组织形貌、空心球等的影响.研究表明:EIGA法制备的TC4合金粉末整体球形度均较好,空心球缺陷较少,空心球率低于3%.熔炼功率较低时,粗颗粒粉末较多,且存在一定比例不规则的棒形和哑铃状粉末颗粒;当功率提高到62 k W时,细粉比例明显提高,不规则形状的粉末颗粒基本消失.随着功率的升高,粉末中的氧含量呈增加趋势,但仍基本保持在0.08%~0.10%较低范围内.功率为56 k W时,粉末松装密度最好,为2.686 g/cm3,松装密度比为60.63%,符合激光3D打印用TC4钛合金粉末松装密度比要求.

Effect of EIGA power parameter on the characteristics of TC4 alloy powder for 3D printing

Different from the traditional atomization technology, electrode induction melt inert gas atomization (EIGA) technology uses pre-alloy bar electrodes with crucibleless induction heating, dripping directly atomization area and then atomized by inert gas. Because the liquid metal during the melting process does not contact with the crucible, the inclusions in the titanium alloy powder can be effectively reduced, and the quality of the alloy powder can be improved. By means of the EIGA equipment designed and developed by ourselves, the effects of power parameter on the properties of TC4 alloy powder, such as size distribution, microstructure and morphology, hollow power were characterized by laser particle size analyzer, scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results show that the TC4 alloy powder prepared by EIGA has better sphericity, less hollow ball defects and less than 3% hollow spheres. At lower melting power, there are more coarse particles and a certain percentage of the dumbbell-shaped and rod powder particles. When the melting power increases to 62 kW, it can be seen that the proportion of fine powder improves obviously and the particles with irregular shapes almost disappear. With the increase of melting power, the oxygen content of the powder shows an increasing trend, but still remains at a low range of 0.08%~0.10%. When the power is 56 kW, the powder has the best apparent density of 2.686 g/cm³ with the apparent density ratio of 60.63%, which meets the requirements for laser 3D printing.