激光熔化沉积铝合金显微组织及力学性能

Microstructure and Mechanical Properties of Aluminum Alloy Deposited by Laser Melting

目的提高激光熔化沉积铝合金的成形质量。方法以颗粒度45~105μm的AlSi10Mg粉末为材料,4045铝合金为基板,利用激光熔化沉积设备在充氩舱内进行铝合金成形试验。测试试样的硬度和拉伸性能,并通过扫描电子显微镜和光学显微镜进行显微组织形貌分析。结果在沉积方向上,试样显微组织呈现周期性条带状纹路,搭接区域呈现出比较明显的弧形特征;含有大量的细密树枝晶。该合金相成分主要包括:Al相、共晶Si相及少量的Mg_(2)Si强化相。沿扫描方向,试样平均硬度值约为130HV;沿沉积方向,试样平均硬度值约为100HV;沉积态试样的屈服强度约为185.75 MPa,伸长率约为15.21%;沉积态试样拉伸性能明显优于压铸试样;该铝合金的失效形式为韧性断裂。结论AlSi10Mg在激光熔化沉积时具有良好的成形能力,沉积态的组织强度高于铸态组织强度。

In order to improve the forming quality of aluminum alloy deposited by laser melting, AlSi10Mg powder with particle size of 45-105 μm was used as material and 4045 aluminum alloy was used as substrate. The aluminum alloy forming experiments were carried out in an argon filled chamber by laser melting and deposition equipment. The hardness and tensile properties of the samples were tested, and the microstructure was analyzed by scanning electron microscope and optical microscope. In the direction of deposition, the microstructure of the sample shows periodic banded patterns, and the lap area shows obvious arc characteristics. The alloy contains a large number of fine dendrites. The alloy phase composition mainly includes Al phase, eutectic Si phase and a small amount of Mg_(2)Si strengthened phase. Along the scanning direction, the average hardness value of the sample is about 130HV. Along the deposition direction, the average hardness value of the sample is about 100HV.The yield strength of the deposited specimen is about 185.75 MPa, and the elongation is about 15.21%. The tensile properties of the deposited samples are obviously better than those of the die-casting samples. The failure mode of the aluminum alloy is ductile fracture. AlSi10Mg has good forming ability during laser melting deposition, and the microstructure strength in deposition state is higher than that in cast state.