Comparing Zinc Castings and Plastics Properties - A Consistent Impact Test Method and Results

After examining several impact tests used for metallic materials and plastics, the ASTM D3029 multi-axial impact test was chosen as a means for obtaining impact energies for zinc Alloy 3 and ZA-8 along with a variety of injection molded engineering plastics. These materials were tested between 25 and 100°C using a range of striker velocities of 1-10 m/sec. Zinc alloys properties were sensitive to impact speed whereas plastics properties were not. The test divided these materials into ductile and more brittle classifications with both polypropylene and the polyamides behaving in the most ductile fashion. Test results are compared with the Charpy impact test for metallic materials and the zinc alloys are shown to possess lower properties using the plastics test, however the zinc alloys possess significantly higher properties using this test when compared to the plastic materials investigated.