Effect of composition and process control agents on the microstructure and ignition properties of ball-milled Al-Zr powders

We demonstrate the effect of varying Al-Zr chemistry on the morphology, microstructure, intermetallic reactions and ignition temperature of powders prepared using arrested reactive ball milling in hexane. Upon slow heating in Ar, 3Al:Zr, Al:Zr, and Al:3Zr (at.%) produces 19 ± 2.6 kJ/mol 22.0 ± 1.6 kJ/mol, and 14.0 ± 2.6 kJ/mol of heat respectively. When rapidly heated in air 3Al:Zr powders did not ignite, while Al:Zr and Al:3Zr had ignition temperatures of 461 ± 25 °C and 475 ± 25 °C, suggesting Zr oxidation is aiding ignition.