Synthesis of Al LM25/TiB2 in-situ composites and investigation of its adhesive wear behavior

Aluminum/titanium diboride (TiB2) in-situ metal matrix composite was produced by reaction between aluminum alloy and potassium hexafluoro titanate (K2TiF6) and potassium tetrafluoro borate (KBF4) salts. Aluminum titanate and aluminum diboride formed during reaction process resulted in formation of TiB2. Energy Dispersive X-Ray analysis was carried out in order to confirm the presence of titanium and boron. Microstructure analysis of composite specimen showed uniform distribution of TiB2 in aluminum matrix. The composite was tested for sliding wear behavior using pin-on-disc tribometer by considering load (10N, 20N, 30N), sliding velocity (1.5m/s, 2.5m/s, 3.5m/s) and distance (750 m, 1250m, 1750m) as parameters. A Taguchi's L-27 orthogonal array was used to optimize process parameters to obtain maximum wear resistance. Analysis of Variance technique was used for statistical analysis for finding parameters having maximum significance with respect to wear rate and Signal-to-Noise ratio was employed to determine their level of influence. Results clearly concluded that load (69.23%) has primary effect on wear rate followed by sliding distance and velocity. Regression model was developed to find relation between wear rate and process parameters. Confirmation tests were conducted and percentage error was found to be less than 10. Scanning Electron Microscopic studies carried out on worn surfaces revealed severe delamination at high loads.