Estimation of the transient interfacial heat flux between substrate/melt at the initiation of magnesium solidification on aluminum substrates using the lumped capacitance method

Interfacial heat flux (IHF) between solid pure aluminum/magnesium melt and solid 413 aluminum alloy/magnesium melt couples was evaluated using lumped capacitance method, and the interface microstructures were assessed by scanning electronic microscope. The variation of maximum IHF with surface roughness for these two couples also was evaluated. The results showed that, for both solid aluminum/magnesium melt couples, with increasing the surface roughness, the maximum IHF increases at first and then starts to decrease after reaching a maximum value. In addition the measured maximum IHF for solid 413 aluminum alloy/magnesium melt couples was found to be higher than those measured for solid pure aluminum/magnesium melt couples. That seems to be because of the better wettability of 413 aluminum alloy than pure aluminum, by magnesium melt.

Research highlights▶ IHF for solid pure aluminum/magnesium melt and solid 413 aluminum alloy/magnesium melt couples is a function of surface roughness. ▶ For both solid pure aluminum/magnesium melt and solid 413 aluminum alloy/magnesium melt couples, by increasing the surface roughness, the maximum IHF increases at first and after reaching a maximum value, starts to decrease. ▶ Almost for all ranges of surface roughness, the maximum IHFs for solid 413 aluminum alloy/magnesium melt couples are higher than those for solid pure aluminum/magnesium melt couples.