摘要
This work investigated the effect of process parameters on densification,microstructure,and mechanical properties of a nickel-aluminum-bronze(NAB)alloy fabricated by laser powder bed fusion(LPBF)additive manufacturing.The LPBF-printed NAB alloy samples with relative densities of over 98.5%were obtained under the volumetric energy density range of 200−250 J/mm^(3).The microstructure of the NAB alloy printed in both horizontal and vertical planes primarily consisted ofβ'martensitic phase and bandedαphase.In particular,a coarser-columnar grain structure and stronger crystallographic texture were achieved in the vertical plane,where the maximum texture intensity was 30.56 times greater than that of random textures at the(100)plane.Increasing the volumetric energy density resulted in a decrease in the columnar grain size,while increasing the amount ofαphase.Notably,β_(1)'martensitic structures with nanotwins and nanoscaleκ-phase precipitates were identified in the microstructure of LPBF-printed NAB samples with a volumetric energy density of 250 J/mm^(3).Furthermore,under optimal process parameters with a laser power of 350 W and scanning speed of 800 mm/s,significant improvements were observed in the microhardness(HV 386)and ultimate tensile strength(671 MPa),which was attributed to an increase in refined acicular martensite.
本工作研究了工艺参数对激光粉末床熔融镍铝青铜合金致密化、微观结构和力学性能的影响。结果表明,在体积能量密度为200~250 J/mm^(3)范围内获得了致密度超过98.5%的镍铝青铜合金样品。激光粉末床熔融镍铝青铜合金样品在水平面和垂直平的微观结构均由β'马氏体和带状α相组成。其中,垂直面具有更粗的柱状晶结构和更强的织构,(100)平面的最大织构强度是随机织构的30.56倍。随着体积能量密度的增加,柱状晶尺寸逐渐减小,α相的数量逐渐增加。在体积能量密度为250 J/mm^(3)成形的镍铝青铜合金样品的微观结构中观察到具有纳米孪晶的β'_(1)马氏体结构和纳米级κ相析出物。此外,在激光功率为350 W、扫描速度为800 mm/s的最佳工艺参数下,显微硬度(HV 386)和极限拉伸强度(671 MPa)显著改善,这归因于针状马氏体的细化及其数量的增加。
基金
Project(2022A1515010304)supported by the Guangdong Basic and Applied Basic Research Foundation,China
Project(52305358)supported by the National Natural Science Foundation of China
Project(2023QNRC001)supported by the Young Elite Scientists Sponsorship Program by China Association for Science and Technology
Project(QT-2023-001)supported by the Young Talent Support Project of Guangzhou,China
Project(2023ZYGXZR061)supported by the Fundamental Research Funds for the Central Universities,China。
