EFFECTS OF LIQUID METAL GATE VELOCITY ON THE POROSITY IN HIGH-PRESSURE DIE-CAST AM50 ALLOY

摘要

Pressure die-cast Mg-alloys usually contain both gas (air) and shrinkage porosity. Quantitative characterization of gas and shrinkage porosity is essential for understanding processing-microstructure-properties relationships. The incoming liquid metal gate velocity is an important process parameter of the high-pressure die-casting process. In this contribution, the microstructures of high-pressure die-cast AM 50 alloy have been quantitatively characterized to understand the effects of in-coming liquid metal gate velocity on the porosity distributions. A novel digital image analysis technique has been used to quantify the volume fraction and other geometric attributes of the gas (air) and shrinkage pores. The differences of the total porosity are mainly due to the differences in the number density of large gas pores.