INFLUENCE OF NUMBER OF PASSES, PROCESSING ROUTE AND AGE HARDENING ON MICROSTRUCTURE, MECHANICAL AND TRIBOLOGICAL PROPERTIES OF ECAPED ALUMINIUM ALLOY ADAPTED DESIGN OF EXPERIMENTS THROUGH TAGUCHI TECHNIQUE

摘要

In this research work, aluminium alloy (AA6063) solutionized at 520°C for 2 hrs, water quenched and then aged at different temperatures such as 160°C, 190°C and 210°C for different ageing times of 2 hrs, 4 hrs and 8 hrs. Then it was subjected to Equal Channel Angular Pressed (ECAP) through different processing routes such as A, Bc and C at room temperature. The sample characterizations were conducted before and after ECAPed specimen using X-ray diffraction (XRD) and EDAX. The ECAPed sample microstructures were studied using Scanning Electron Microscope (SEM). It was confirmed that the grain size reduction and additional peak were observed after ECAP, compared to cast specimen. In order to predict the influence of process parameters such as number of passes, processing route, ageing temperature, ageing time interval, load and sliding distance on tribological behaviour of ECAPed specimen, dry sliding wear test was conducted using Pin on Disc machine against a steel disc. Then the process parameters and their influences were optimized using Design of Experiment (DoE) through Taguchi technique and confirmed through Analysis of Variance. The result depicts that the combination of pre-ageing with number of passes in ECAP has improved the micro hardness and wear resistance of AA6063.