采用区域选择激光熔化技术直接制造铝合金零件

区域选择激光熔化技术(SLM)与选区烧结技术(SLS)相比其突出的特点在于SLM过程使用的金属粉末为单组元粉末材料以及该过程中金属粉末完全熔化。因而采用SLM技术生产的金属功能模型和零件致密度高，具有系列产品的组织结构和使用性能,为单件、小批量直接制造金属零件提供了可能。介绍了SLM技术的特点以及采用SLM技术加工铝合金粉末的特殊性,采用SLM工艺熔化金属在随后的结晶过程中易出现成球现象,优化激光加工参数以及在加工过程中通入惰性气体可以克服该问题。采用SLM技术加工了AlSi25和AlSi10Mg两种铝合金粉末,制备了样件和拉伸试样。微观分析显示:样件的横截面中均无孔隙和裂纹存在,组织细小,微观结构分为细晶区和搭接区,搭接区的结构明显长大,经拉伸测试,采用SLM技术生产的样件具有优于传统方法生产试样的综合机械性能。给出了采用SLM技术制造的铝合金功能模型。

Direct Manufacturing of Aluminium Parts by Selective Laser Melting

Selective laser melting (SLM) is distinguished for its characters that using of single component metal powder and complete melting of metal powder compared with selective laser sintering (SLS). So the metallic functional model and parts manufactured by SLM possess of fine microstructure and using properties similar to series production, and makes the direct manufacturing of metallic parts by single or small lot possible. The character of SLM and speciality of aluminium powder radiated by SLM process are briefly introduced. Balling phenomena during solidification of molten metal always take place when laser radiates aluminium powder by SLM, the methods such as optimizing of laser processing parameters and flowing of inert gas to overcome it are introduced. The powder of two aluminium alloys AlSi25 and AlSi10Mg are radiated with laser and the samples are made. The microstructure analysis showed that there is no pore and crack in the cross section, the thin microstructure can be divided into thin particle and overlapping zone, the microstructure in the overlapping zone obviously grew. The tensile test proved that the samples manufactured by SLM is distinguished for its excellent properties compared with the sample made from conventional methods. Functional model from aluminium alloys manufactured by SLM is proposed at last.