Diagnosis of Oxide Films in Cast Aluminum Alloys

Abstract

Aluminum (Al) alloy castings often contain many defects, such as micro-shrinkage, gas pores, shrinkage pores, hot tearing, and oxide film entrapment. When oxide films are entrapped in Al alloy castings, they are very difficult to identify simply by optical observation. In this study we used an auto-scanning eddy current testing method to detect oxide films entrapped in Al alloy castings. The detection signal and the measurement data were confirmed by scanning electron microscope (SEM) observation and partly backed-up by the ultrasonic-vibration method.