电子束熔丝沉积4043/4074铝合金的组织与力学性能

目的 研究电子束熔丝沉积Al-Si合金的微观组织与力学性能以及后续热处理的影响。方法 采用电子束熔丝沉积快速成形技术，分别对直径2 mm的4043和4047铝合金丝材进行增材制造成形，研究样品在不同方向上的微观组织与力学性能以及后续热处理的影响。结果 打印态的4043和4047合金的致密度分别为99.81%和99.88%，热处理后略有降低，分别为98.94%和99.77%。打印态样品中含有一些由硅颗粒和杂质相组成的条带状微观组织。打印态样品中含有近似等轴状与棒状的两类细小Si颗粒。打印态样品在长、宽、高3个方向上的拉伸强度相当，4043合金的抗拉强度为120~127 MPa，伸长率为12%~30%；4047合金的抗拉强度为151~155 MPa，伸长率为15%~30%。经热处理后，样品的强度略有降低，但伸长率显著提升。结论 通过控制EBF3参数，可以获得致密无缺陷的具有良好力学性能的块体Al-Si合金样品，其力学性能可通过后续热处理进一步调控。

Microstructure and Mechanical Properties of 4043/4047 Al Alloy by Electron Beam Freeform Fabrication

The paper aims to investigate microstructure and mechanical properties of Al-Si alloys deposited by electron beam fusing wire and effects of subsequent heat treatment. 4043Al and 4047Al alloy wires with a diameter of 2 mm were subjected to additive manufacturing by electron beam freeform fabrication (EBF3). Microstructure and mechanical properties of the samples in different directions and effects of subsequent heat treatment were investigated. The densities of the printed 4043Al and 4047Al samples were 99.81% and 99.88%, respectively, and they decreased slightly to 98.94% and 99.77% after heat treatment. The printed samples contained some banded microstructures consisting of silicon particles and impurity phases. Two kinds of fine Si particles with equiaxed or rod-like morphologies were found in the as-printed samples. The tensile strength of the presented samples was similar in three directions: for the 4043Al, the strength was 120~127 MPa and the elongation was 12%~30%; for the 4047Al, the tensile strength was 151~155 MPa and the elongation was 15%~30%. After heat treatment, the tensile strength of the samples decreased slightly, but their elongations increased significantly. Dense bulk of Al-Si alloys with good mechanical properties can be printed without macroscopic defects under selective EBF3 parameters, and their mechanical prop¬erties could be further modified by subsequent heat treatment.