气体雾化法制备Al基非晶合金粉末工艺及组织结构

针对3D打印用Al基非晶合金粉末的性能需求,利用惰性气体雾化法制备Al_(86)Ni_7Er_5Co_1La_1合金粉末.通过调整过热度、雾化气压、导流管直径来分析不同雾化工艺参数对粉末粒径的影响规律;利用激光粒度分析仪、X射线衍射仪(XRD)、扫描电子显微镜(SEM)和差示扫描量热仪(DSC)对粉末的粒度分布、物相组成、表面形貌、微观组织结构和热稳定性进行分析测试.研究表明:合金粉末的粒径随着雾化气压的增加、导流管直径的减小和过热度的增加而逐渐降低.当过热度100℃、雾化气压9 MPa、导流管直径3 mm时,细粉率最高,其中粒径75μm粉末的质量分数在70%以上.随着粉末粒径的减少,合金粉末的组织结构发生了如下转变:fcc-Al+Al_(17)Er_2+未知相→非晶相+fcc-Al+Al_(17)Er_2+未知相→非晶相+fcc-Al→非晶相,粒径小于25μm的粉末为完全的非晶态.

Preparation and Structure of the Al-based Amorphous Alloy Powder by Gas Atomization

In order to produce the Al-based amorphous powder that could meet the requirement for 3D printing, the Al86 Ni7 Er5 Co1 La1 alloy powder was prepared by gas atomization. The effect of the gas atomization parameters on the particle size were analyzed though adjusting the superheat, gas pressure, and diameter of the tube. The size distribution, phase composition, surface morphology, micro-structure and thermal stability of the alloy powder were detected through laser particle analyzer, X-ray diffraction ( XRD ) , scanning electron microscope ( SEM ) , and differential scanning calorimetry ( DSC ) . It indicates that the particle size of the alloy powder decreases with the increase of gas pressure, decrease of the diameter of tube and increase of the superheat. The highest fine powder rate was obtained when the gas parameter was as the followings, overheat 100℃, gas pressure 9 MPa, diameter of tube 3 mm, the mass fraction of the powder with particle size of less than 75μm could be above 70%. With the decrease of the particle size of the powder, the structure of the powder transformed as the followings, fcc-Al +Al17 Er2 + unknown phase →amorphous + fcc-Al + Al17 Er2 + unknown phase→fcc-Al +amorphous→amorphous, the powder with size of less than 20μm was all amorphous state.