Microstructure and Wear Resistance of Semisolid TiB₂/7050 Composites Produced by Serpentine Tube Pouring Technique

Abstract

TiB₂/7050 (3, 6, and 9 wt%) composites slurries with globular were synthesized by in situ reaction and serpentine tube pouring techniques. The results showed that the semisolid 7050 alloy and 3, 6, and 9 wt%TiB₂/7050 composites with average grain diameter of 28, 25, 20, and 19 µm and shape factor of 0.77, 0.83, 0.90, and 0.93, respectively, can be obtained at 660 °C pouring temperature. With increasing TiB₂ content and curves number, the α-Al grain size was decreased. The composite melts have an effect of “self-stirring” when they flow through the serpentine tube, which is beneficial to make the primary nuclei with globular grains. Moreover, the wear resistance of TiB₂/7050 composites improved obviously with increasing in situ TiB₂ particles content and that the wear rate of 9 wt%TiB₂/7050 composite was 79% lower than that of 7050 matrix alloy under 100 N applied load, 30 min sliding time, and 0.15 m/s sliding velocity.

Keywords:

• 7050
• Wear
• Abrasion
• Aluminum
• Composites
• Microstructure
• Semisolid
• TiB₂