Wettability and Heat Transfer During Impingement of Al-Mg alloy (AA 5356) Droplets on AA 5356 Substrates
摘要
Wettability and heat transfer during impinging of AA5356 alloy melt droplets were studied in the present work. Experiments were conducted for varying currents in the range 60–100 A. The metal droplets were deposited on the cylindrical substrates of 20 mm diameter with 40 mm (Cs) and 60 mm (Cb) length. The temperatures were recorded for the estimation of heat flux transients and heat flow to the substrates by inverse heat conduction analysis. The heat flow was 3.5 MJ/m2 and 11.6 MJ/m2, respectively for a single cycle of deposition on CS for 60 A and 110 A, respectively. The heat flow increased to 7.2 MJ/m2 and 18.3 MJ/m2 for the dual cycle deposition. The experiments were also carried out on Cb to study the effect of heat flow on dimensions of substrate. Higher values of heat flow at higher currents increased the porosity and micro-hardness. Coarser grains were obtained at higher currents. The average surface roughness (Ra) was found to be 152.3 µm for lower value of currents with small pores present near grain boundaries. For a moderate current values of 80–90 A, the Ra was found to be 26.32 µm with minimum porosity. Line deposition carried out using identical parameters exhibited characteristics consistent with those observed during droplet deposition. The findings of the present work can be applied in wire arc additive manufacturing of AA5356 to enhance the bonding between layers, deposition stability and minimize defects such as porosity and voids.