Microstructural effect of the L.H.I.P. process on the A356 aluminium alloy
An extended investigation of the microstructure of A356 both as cast and processed by Liquid Hot Isostatic Pressing (LHIP) was performed using TEM, SEM and X-ray diffraction techniques. Specimens of the alloy in both conditions were solutionised for 8h at 520°C and aged for 6h at 160°C. TEM investigations revealed no significant influence of the L.H.I.P. process on particle precipitation kinetics and morphology.
Pores were investigated and characterised by means of light and electron microscopy and statistical techniques. L.H.I.P. treatment reduced the pores mean size by about 1/3, the volume fraction by one order of magnitude and the shrinkage voids in number and volume.