The structures and compositions of Ti and Zr rich phases in ternary Al－Ti－Zr and quaternary Al－Si－Ti－Zr systems were investigated by energy dispersive spectroscopy and X-ray diffraction. The additions of Ti and Zr were changed. It was found that Ti and Zr can replace each other in the Ti and Zr rich phases of Al－(Si－)Ti－Zr alloys. Compositions of the phases have been measured as a function of Ti and Zr additions. The content of Ti (Zr) in the phases increases with its addition in the alloys. Besides, the increase of Ti content can result in a decrease of lattice parameters. Microhardness of the phases in Al－18Si－xTi－yZr alloys changes with composition evolution. Moreover, the microhardness is higher than that of the intermetallics of ternary Al－Si－Ti and Al－Si－Zr alloys, due to the distortion of crystal structure caused by the replacement of Ti and Zr.
Received: 08 May 2012
Published: 19 March 2013
National Basic Research Program of China (973 Program, No. 2012CB825702) and the National Natural Science Foundation of China (No. 51071097).