Eventos Anais de eventos
COBEF 2017
Congresso Brasileiro de Engenharia de Fabricação
STRENGTHENING MECHANISMS IN AN Al-0.9Mg-0.2Zr (wt.%) ALLOY AFTER ISOTHERMAL AGING
Submission Author:
Pedro Lamarão , SC
Co-Authors:
Carlos Augusto Silva de Oliveira, JOSÉ MARIA DO VALE QUARESMA
Presenter: Pedro Lamarão
doi://10.26678/ABCM.COBEF2017.COF2017-0435
Abstract
The present work quantifies the active strengthening mechanisms due to solid solution and precipitation hardening in an Al-0.9Mg-0.2Zr (wt.%) alloy, using literature models, microstructural characterization with a Transmission Electron Microscope – TEM and Vickers microhardness tests. The studied alloy was conventionally cast and isothermally aged at the temperature of 650 or 700 K (377 or 427 ºC) for 4, 12, 24, 100 and 400 h. The microhardness of the as-cast samples presented an increase of 136 MPa (13.9 HV 0.2), attributable to solid solution strengthening from Mg, comparing to an Al-0.2Zr alloy. Samples aged at 650 K presented an increase in strength after 24 h of aging and peak-strength after 100 h, while after 400 h it presented the same microhardness of the as-cast samples. During aging at 700 K no significant increase in strength was observed. Nanometer-scale Al3Zr, with a mean radius of 8 nm, and β-Al3Mg2, with a mean radius of 235 nm were identified in the microstructure of the alloy. Comparing the increase in strength due to the studied mechanisms, one obtained good agreement between the experimental and theoretical results.
Keywords
Al alloys, Precipitation hardening, Solid solution hardening, Strengthening Mechanisms
