Microstructure, Mechanical Properties and Strengthening Mechanism Analysis in an AlMg5 Aluminium Alloy Processed by ECAP and Subsequent Ageing

Abstract

A coarse-grained microstructure of solution treated AlMg5 aluminium alloy was prepared by equal channel angular pressing through route BC. Microstructure evolution of the alloy was analysed by using an optical microscope, X-ray diffraction, and EBSD (electron backscatter diffraction). The results reported that grains were refined due to the interactions of shear bands with low-to-moderate grain boundaries, and this structure was transformed into a bimodal after ageing at 180 °C for 4 h. Moreover, the results of the tensile testing showed that the yield strength was increased from 110 to 326 MPa, and the corresponding tensile strength increased from 269 to 395 MPa, maintaining an appropriate elongation of ~18%. After ageing at 180 °C elongation increased to 23% and the sample still kept high yield strength of 255 MPa, which may be associated with the mutual influence of the dislocation density decrease and recrystallization processes.

The Effect of Isothermal Multi-Directional Forging on the Grain Structure, Superplasticity, and Mechanical Properties of the Conventional Al–Mg-Based Alloy

“…As a result, a bimodal grain size distribution was observed in the central cross-section after IMF at 350 • C and ∑e = 6.3. Similar grain bimodality was observed after multi-directional forging of various aluminum alloys [9,[27][28][29][30][31] and after IMF with a lower strain per pass of 0.4 and a cumulative strain of ∑e = 6.1 in the studied Al-Mg-Mn alloy [43].…”

“…The grain structure consists of very fine grains and coarse grains in pure Al subjected to multi-directional forging at room temperature [25,26]. Similar grain bimodalities are observed in many aluminum-based alloys [9,21,[27][28][29][30][31]. The final grain structure and its homogeneity are 2 of 12 significantly affected by the deformation temperature, cumulative strain and alloy composition [2,[7][8][9][10]20].…”

A Review of Microstructural Evolution and Modelling of Aluminium Alloys under Hot Forming Conditions

“…During these operations, microstructural processes of recrystallisation and grain growth, accompanied by dislocation accumulation and recovery [7] may occur and affect the formability. Furthermore, the final microstructures in a formed part, which may vary according to the location of the part, determine the post-forming mechanical properties, including strength, ductility and fatigue life [8,9]. Therefore, a deep understanding of the underlying microstructural evolution, the relationships between microscopic and macroscopic behaviour and the macroscopic responses of interest during hot deformation are vitally important for optimising the forming windows to achieve components with the desired geometries and in-service properties.…”

Effects of modifying the hypoeutectic AlMg5Si2Mn alloy via addition of Al10Sr and/or Al5TiB

“…AlMg5Si2Mn is a non-heat-treatable 5xxx series aluminum foundry alloy that contains Mg and Si as major alloying elements. This alloy exhibits good corrosion resistance, hardness, and thermal conductivity, so it is typically utilized as a lightweight material for structural components in the automotive and aerospace industry [1][2][3]. The microstructure of Al-Mg-Si cast alloys, including AlMg5Si2Mn, consist of α-Al dendrites, primary Mg 2 Si particles, and/or brittle α-Al + Mg 2 Si "Chinese script" eutectic structures [4].…”