Iuri Boromei

Friction Stir Welding of Aluminium Based Composites Reinforced with Al2O3 Particles

This paper presents the results of microstructural and mechanical characterization of Friction Stir Welding joints of two aluminum-based particles reinforced composites. The composites were FSW in the extruded and T6 heat treated condition. No post-weld heat treatment was carried out on the FSW joints. Hardness, tensile, low-cycle fatigue and impact tests were carried out. Microstructural and fractographic characterization were performed both on the base and FSW material, in order to investigate the effect of the solid-state welding process on the reinforcement particles and aluminum matrix. The FSW produced high quality joints with good microstructural characteristics: the welded zone displayed a refinement of the Al matrix grain size and reinforcement particles, and a better particle distribution. The FSW specimens showed high efficiency, both in the tensile, impact and fatigue tests.

Microstructure Prediction in Aluminium Extrusion by Means of FEM Simulation

An original inverse extrusion test was developed in order to study the microstructural evolution in the plastic deformation of 6060 and 6082 aluminium alloys. Sample billets were extracted from commercial logs and subjected to plastic deformation in an inverse extrusion process, particularly aimed at producing different strain and strain rate conditions at representative positions within the billet section. Different experiments were performed at various temperatures and strain rates. The particular thermo-mechanical history of each point in different experiments was then reconstructed by FEM analysis. The cups were sectioned and the microstructure was analysed at some representative locations, to relate it to the FEM simulation results.