리싸이클링된 AM50 마그네슘 합금의 개재물과 청정도 평가에 관한 연구

Abstract

Magnesium alloys have many benefits such as light-weight, damping capacity and electromagnetic wave shield, etc, so have been applied to various industrial fields, the consumption of which are projected to grow during next decades, especially in the automotive and electronic industries. The magnesium components are mainly fabricated by die casting process, and it has been studied for Mg scrap because this process makes lots of scrap. This study is on the evaluation of the cleanness of AM50 recycling melt and ingot , which contains the methods of analyzing chemical compositions, measuring the amount of inclusions . AM50 is used in automotive parts because of its high elongation This study is focus in brightness method using brightmeter, which is to identify the brightness of the fracture surface of specimen. The brightness is low when a lot of oxides or inclusions are present on the surfaces. Specimens are prepared with melt or ingot. After analyzing elements, fracture specimens by an impact and evaluate the brightness of the fractured surface using a spectrophotometer. Test specimens of various condition for filtration or not and degassing or not, and evaluate scanning electron microscopy (SEM) combined with energy-dispersive spectrometry (EDS) and MgO fraction finally. Generally, brightness decreased with increasing alloying elements(Al, Zn etc), it is result in increasing β-phase, intermetallic compound. Finally, AM50 has brightness value over 50, and the value decrease by increasing oxide. Treated filtration and degassing specimens have higher value.