This study investigated the impact of the equal channel angular pressing (ECAP) combined with heat treatments on the microstructure and mechanical properties of AlSi10Mg alloys fabricated via selective laser melting (SLM) and gravity casting. Special attention was directed towards determining the effect of post-fabrication heat treatments on the microstructural evolution of AlSi10Mg alloy fabricated using two different routes. Three initial alloy conditions were considered prior to ECAP deformation: (1) as-cast in solution treated (T4) condition, (2) SLM in T4 condition, (3) SLM subjected to low-temperature annealing. Light microscopy, transmission electron microscopy, X-ray diffraction line broadening analysis, and electron backscattered diffraction analysis were used to characterize the microstructures before and after ECAP. The results indicated that SLM followed by low-temperature annealing led to superior mechanical properties, relative to the two other conditions. Microscopic analyses revealed that the partial-cellular structure contributed to strong work hardening. This behavior enhanced the material’s strength because of the enhanced accumulation of geometrically necessary dislocations during ECAP deformation.
The effect of 2 mass% rare earth elements (RE) as in mischmetal state on the structure, thermal behaviour and mechanical properties of Mg-xLi-4Al (x = 4, 8 and 12 by mass percentage). The thermo-derivative analysis was implemented using the UMSA platform (Universal Metallurgical Simulator and Analyzer) with cooling rate approx. & 0.6°C s -1 that correspond to natural cooling. Microstructural evaluations were identified by X-ray diffraction, scanning electron microscopy, light microscope and energy-dispersive X-ray spectroscopy. Obtained results from the thermal derivative analysis allowed determining the solidification pathways for Mg-Li-Al-RE alloy. The addition of grain refinement causes changes in crystallisation process. The addition of RE elements affected an enhancement in mechanical properties, which was associated with the development of intermetallic compounds; the maximum increases in hardness at level 240% was observed for single a-phase alloy and at level 19% for a ? b alloy.
The binary as-cast Al–Cu alloys Al-5%Cu, Al-25%Cu, and Al-33%Cu (in wt %), composed of the intermetallic θ-Al2Cu and α-Al phases, were prepared from pure components and were subsequently severely plastically deformed by extrusion combined with reversible torsion (KoBo) to refinement of α-Al and Al2Cu phases. The extrusion combined with reversible torsion was carried out using extrusion coefficients of λ = 30 and λ = 98. KoBo applied to the Al–Cu alloys with different initial structures (differences in fraction and phase size) allowed us to obtain for alloys (Al-25%Cu and Al-33%Cu), with higher value of intermetallic phase, large elongations in the range of 830–1100% after tensile tests at the temperature of 400 °C with the strain rate of 10−4 s−1. The value of elongation depended on extrusion coefficient and increase, with λ increasing as a result of α-Al and Al2Cu phase refinement to about 200–400 nm. Deformation at the temperature of 300 °C, independently of the extrusion coefficient (λ), did not ensure superplastic properties of the analyzed alloys. A microstructural study showed that the mechanism of grain boundary sliding was responsible for superplastic deformation.
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