Effects of Titanium and Boron Additions with Mechanical Stirring on Mechanical Properties in Al-Si Alloys

Abstract

Al-Si based alloys are widely used to automobile parts for weight reduction. The mechanical stirring method was performed to achieve the homogeneously dispersed strengthening phases such as AlB 2 , Al 3 Ti and TiB 2 phases since the specific gravity of strengthening phases is different from the Al matrix. 500 rpm of mechanical stirring results in well dispersion of strengthening phases compared with lower speed (100 rpm) and higher speed (1,000) stirring rate. The higher elastic modulus, hardness and good wear resistance is obtained in the Al-12 mass%Si-2.3 mass%Ti-1 mass%B alloy due to the formation of strengthening phases such as Al 3 Ti and boride containing (AlTi)B 2 compared with Al-12 mass%Si, Al-12 mass%Si-2.3 mass%Ti and Al-12 mass%Si-1 mass%B alloy. Relationship between the microstructure and mechanical properties is discussed based on the solidification phenomena.

Ultrasonic-Assisted Brazing of Titanium Joints Using Al-Si Based Fillers: Numerical and Experimental Process Design

“…Ti could be a contributor in reducing the primary silicon with the assistance of the ultrasonic vibration. It was found that the addition of the Ti reduced the formation of primary silicon [34]. In another study, TiAl 3 was found at the surface of the Si phase, which restricted the growth of Si [35].…”