Study on AZ91D chip for injection molding (1st Report, Effect of dimension on bulk density after consolidation)

Abstract

The purpose of this study is to propose an effective model to estimate the filling fraction of compacts made from magnesium alloy particles, considering the effects of particle size, temperature and pressure. In order to investigate the influence of the particle size, six kinds of particles were prepared in which the cross sectional area was different. The test particles made from AZ91D were poured into a compression vessel and then a given pressure was applied to the piston of vessel for six hours under constant temperature condition. During the testing, the displacement of piston was measured to evaluate the change of bulk density of compacts, and then the filling fraction was simply calculated by the ratio of bulk density of compacts and density of AZ91D. Test results showed that the filling fraction of the largest particles was lower than that of other particles in the temperature region between 523 K and 623 K. The densification rates of compacts were increased with increase of applied pressure and temperature elevation. The experimental equation of densification rates of compacts was determined to discuss the effects of cross sectional area on densification rate. Determination results showed that the transition point to the steady creep was increased with increase of cross sectional area of particles.

Keywords

• bulk density
• filling fraction
• densification rate
• magnesium alloy
• thixomolding