A356 alloy foam fabrication by melting method using titanium hydride

Department of Materials Science and Engineering, Yazd Branch, Islamic Azad University, Yazd, Iran
zohairsarajan@iauyazd.ac.ir; zohairsarajan@yahoo.com

Received: 21 November 2014
Accepted: 13 April 2015

Abstract

Metallic foams have been of considerable interest both from the industrial applicability and scientific viewpoint. Nevertheless, besides the cost aspects, there are a lot of technical improvements necessary in order to gain more widespread use. The present study focused on thermal decomposition behavior of titanium hydride on the melt foaming during casting and unidirectional solidification of A356 alloy. Therefore, the effects of heating temperature, stirring time and TiH2 wt. %, on percentage of porosity have been investigated. It was found that under optimum torque-temperature conditions and TiH2 addition of 1.0–1.5 wt. %, a remarkable foaming efficiency could be achieved. Foamed A356 cross-sections were microscopically characterized by Scanning Electron Microscopy corresponding to different TiH2 contents. The optimum amount of titanium hydride content induces uniformity in porosity cell structure distribution in the whole cross section of the foamed aluminum. Medium thickness of thin cell wall is near to 20 μm which is easily broken or disrupted.