Effect of Isothermal Holding on Semisolid Microstructure of Al–Mg2Si Composites

Abstract EN

Effect of heat treatment and isothermal holding has been investigated on the microstructure and degree of globularity of Al–Mg2Si composites.

Different contents of reinforcement, 15, 20, and 25% have been used in this study.

Isothermal holding experiments were conducted at 585 °C for 140 min.

Results showed that, upon heat treatment, grain size of dendrites was reduced while the degree of nodularity was increased.

Results of nodularity were obtained using an image-analyzing software which gives the distribution of radius of curvature for different phases of particles.

According to the results, in contrast to Al–15 and 25% Mg2Si, isothermal holding significantly influenced the microstructure of Al–20% Mg2Si composites.

Two companion mechanisms have been proposed for the generation of globular grains.

SEM investigations were also employed to confirm the optical observations.