Enhancing the mechanical and tribological properties of aluminum (3XX.X) alloys through alloying addition and laser-assisted surface modification

Abstract

The investigation embodied in the thesis entitled “Enhancing the Mechanical and Tribological Properties of Aluminum (3XX.X) Alloys Through Alloying Addition and Laser-Assisted Surface Modification” was initiated in Dec 2017 in the Discipline of Metallurgy Engineering & Materials Science, Indian Institute of Technology Indore. The Al-Si-based cast alloys have become the most desirable material for automobile, aerospace, and military applications. But for existing Al-Si-based cast alloys the service temperatures are limited up to 130-150°C. Beyond this temperature, recrystallization and grain coarsening will occur and lead to quick deterioration in mechanical as well as tribological properties. Therefore, my thesis work aims in improving the strength of Al-Si-based cast alloys with enhanced elevated temperature mechanical and wear properties by adopting various strengthening mechanisms like alloying addition through liquid metallurgy (casting) route and by using pulsed laser-assisted surface engineering techniques. The primary objectives of the thesis work are listed as follows: i) To study the effect of minor Zr addition to the Al-Si-Cu-Ni based cast alloy on microstructure, mechanical, and elevated temperature (200˚C) fretting wear behavior. ii) To investigate the effect of pulsed laser-assisted nitriding in different environments namely (in an open atmosphere with and without N2 gas purging, and liquid nitrogen environment) on nitride layer thickness, surface mechanical, and elevated temperature tribological properties of Al-Si based cast alloys. iii) To optimize the key process parameters during the laser-nitriding process such as laser fluence, N2 gas flow rate, laser wavelength, etc.