Solution strengthening and age hardening capability of Al–Mg–Mn alloys with small additions of Cu

Abstract

Nine Al-(1-3)Mg-(0-0.4)Cu-0.15Si-0.25Mn (in wt%) alloys with potential applications in both packaging and automotive industries have been investigated. Tensile testing showed that solution strengthening is in good approximation linearly proportional to the Mg content. Mechanical testing and microstructural examinations of aged samples indicate that Mg 2 Si phase precipitates contribute to age hardening of Cu-free alloys, whilst both Mg 2 Si phase and S (Al 2 CuMg) phases contribute to that of Cu-containing alloys. The age hardening capability is critically influenced by solution treatment temperature: increasing the solution treatment temperature from 500 to 550ºC results in a marked increase in rate of hardening for Cu containing alloys and solution treatment at about 550ºC or higher is needed to allow Mg 2 Si phase precipitation during ageing in Cu-free alloys with Mg content of about 2% or higher.

Al–Mg–Cu based alloys and pure Al processed by high pressure torsion: The influence of alloying additions on strengthening

“…However, increasing the Mg content from 1 to 3 wt% causes a much stronger rise of microhardness, which indicates Mg addition can effectively improve strengthening during HPT processing. Previous studies reported that the strength of Al-Mg-Cu alloys increases approximation linearly with Mg content [13,24]. In the present SPD alloys also the interaction between Mg content and dislocations is important.…”

“…The Al-1050 had been extruded into a rod with grain size of 45μm. The cast Al-1Mg, Al-1Mg-0.4Cu and Al-3Mg-0.4Cu ingots were preheated and homogenised at 540ºC, and subsequently hot rolled down to 5 mm in thickness [13]. After that, the hot rolled sheets were solution treated at 500ºC for 20 minutes, followed by cold rolling to 10% reduction, and grain size is about 30 ×100 µm.…”

“…4.2 The evolution of microstructure in Al-Mg-Cu alloys during HPT Addition of 0.4wt% Cu to Al-1Mg causes a small improvement in strength and hardness both in solution treated and subsequently rolled condition (see [13]). The present results also show that after severe plastic deformation using HPT, the Cu addition increases hardness slightly (Fig.…”

“…The Al-Mg-Cu alloys with low Cu (<0.5wt%) content that are being studied in this work span compositions of alloys that have been widely used in beverage cans for decades [11], to compositions that are now increasingly being used as car body panels to reduce weight and thus improve fuel economy and reduce emissions [12]. In these applications they derive their strength mostly from solution strengthening and strain hardening [13]. The Al-Mg-Cu alloys with higher Cu content (>2.5wt%) that are being studied in this work are applied predominantly in the aeronautical industry due to their in-service strength, which is due primarily to precipitation hardening [14,15,16,17], combined with good damage tolerance properties [18].…”

Microembossing of ultrafine grained Al: microstructural analysis and finite element modelling

“…The ECAP process was conducted up to 12 passes; further details on ECAP processing are provided in [28]. The Al-Mg-Cu-Mn alloy with composition Al-2.90Mg-0.40Cu-0.25Mn-0.19Fe-0.15Si (in wt%) was produced by direct chill casting, then preheated and homogenized at 540 • C, hot rolled down into 5 mm thickness, solution treated at 500 • C for 20 min, and cold rolled to 10% reduction (details are provided in [29]). The rolled plate was cut to HPT discshaped samples of 10 mm diameter and 0.8 mm thickness.…”