Effect of Heat Input on Formability, Microstructure, and Properties of Al–7Si–0.6Mg Alloys Deposited by CMT-WAAM Process

Abstract

In order to improve the forming efficiency of Al–7Si–0.6Mg fabricated by wire and arc additive manufacturing process (WAAM), wire with a diameter of 1.6 mm was selected as the raw material. The effect of heat input on the formability, microstructure, and properties of the WAAM alloy was investigated, and the forming model was established. The WAAM alloys were characterized by electronic universal testing, scanning electron microscopy, energy spectrum analysis, and metallographic microscopy. The results show that Al–7Si–0.6Mg alloy has a large processing window under the cold metal transfer (CMT) process, and it can be well formed with a large range of heat input. The secondary dendrite arm spacing and Fe-phase in the as-deposited alloy gradually increase with an increase in heat input, and slight overburning occurs in the heat affected zone at higher heat inputs. After solid solution and aging treatment (T6 heat treatment), the size of α-Al grain and eutectic silicon grain increases with the increase of heat input. Little anisotropy in the mechanical properties is observed except at higher heat inputs. The tensile strength is 354.5 MPa ± 7.5 MPa, yield strength is 310 MPa ± 5.5 MPa, and elongation is 6.3 ± 0.7%.

Review of Aluminum Alloy Development for Wire Arc Additive Manufacturing

“…The Al-7Si-0.6Mg (4220) alloy is suitable for melting-based processing without tendency to crack [ 128 ]. Thus, these alloys are well-suited for WAAM combined with artificial aging [ 129 , 130 ]. Yang et al showed that 4220 in as-deposited state has a relatively poor tensile strength of 130 , but can be raised to 350 in T6 state [ 131 , 132 ].…”

Визначення Оптимальних Параметрів Процесу Waam На Основі Технології CMT З Використанням Низьковуглецевої Нелегованої Сталі

“…Погонну енергію для експериментальних пар параметрів (рисунок 6) було визначено за наступною формулою [6]:…”

In situ alloying of aluminium-based alloys by (multi-)wire-arc additive manufacturing

“…Visually the microstructure is comparable to the microstructures reported in Refs. [20,21], which were fabricated by single wire WAAM but differs significantly from microstructures observed after selective laser melting (SLM) [22].The microstructures obtained after SLM are dominated by the severe nonequilibrium condition of the feedstock alloy powders and the subsequent intrinsic heat treatment being repetitive in nature, but due to the particularly small melt pool, cooling rates are much higher than during WAAM. EDX analysis was used for the identification of additional constituents visible in Fig.…”