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A supersaturated Al-4.8%Zn-1.2%Mg-0.14%Zr (wt%) alloy was processed by the equal-channel angular pressing (ECAP) technique at room temperature in order to obtain an ultrafine-grained (UFG) microstructure having an average grain size of about 260 nm. The hardness and microstructural characteristics, such as the phase composition and precipitations of this UFG microstructure were studied using depth-sensing indentation (DSI), transmission electron microscopy (TEM), as well as non-isothermal scanning of differential scanning calorimetry (DSC), and compared to the properties of the un-deformed sample. Emphasis was placed on the effect of the UFG microstructure on the subsequent thermal processes in DSC measurements. It has been shown that the ECAP process resulted in not only an ultrafine-grained but also a strongly precipitated microstructure, leading to a hardness (2115 MPa) two and a half times higher than the initial hardness of the freshly quenched sample. Because of the significant changes in microstructure, ECAP has also a strong effect on the dissolution (endothermic) and precipitation (exothermic) processes during DSC measurements, where the dissolution and precipitation processes were quantitatively characterized by using experimentally determined specific enthalpies, ΔH and activation energies, Q.
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http://dx.doi.org/10.3390/ma16196593 | DOI Listing |
Sci Rep
July 2025
Department of Materials Science and Engineering, Sharif University of Technology, Azadi Avenue, Tehran, Iran.
The primary objective of this study is to determine the most effective solution treatment and aging temperature for AA2024 aluminum alloy to achieve superior mechanical properties. In this research, a Severe Plastic Deformation (SPD) method known as Multi-Directional Forging (MDF), which is one of the useful methods for creating Ultra-Fine Grained (UFG) microstructure, was employed on AA2024. Due to the limited studies on the effects of artificial aging on this alloy in its supersaturated state following the MDF process, the alloy was subjected to solution treatments at 480 °C, 500 °C, and 520 °C for 1 h, followed by immediate MDF.
View Article and Find Full Text PDFMaterials (Basel)
March 2025
Key Laboratory for Light-weight Materials, Nanjing Tech University, Nanjing 211816, China.
Thermomechanical processing by applying deformation-induced ferrite transformation (DIFT) is an effective method of producing ultrafine-grained (UFG) ferritic steels, which usually present high yield strength but low strain hardening. In this study, we explored the concept of DIFT in the processing of UFG dual-phase (DP) steel, in order to improve its strain hardening capability and thus its ductility. The processing temperature was reduced to enhance the dislocation storage in austenite.
View Article and Find Full Text PDFNat Commun
November 2024
Department of Civil & Systems Engineering, Johns Hopkins University, Baltimore, MD, USA.
Creating statistically equivalent virtual microstructures (SEVM) for polycrystalline materials with complex microstructures that encompass multi-modal morphological and crystallographic distributions is a challenging enterprise. Cold spray-formed (CSF) AA7050 alloy containing coarse-grained prior particles and ultra-fine grains (UFG) and additively manufactured (AM) Ti64 alloys with alpha laths in beta substrates. The paper introduces an approach strategically integrating a Generative Adversarial Network (GAN) for multi-modal microstructures with a synthetic microstructure builder DREAM.
View Article and Find Full Text PDFActa Biomater
November 2024
Graduate School of Peking Union Medical College, Beijing 100730, China; School of Materials Science and Engineering, Peking University, Beijing 100871, China. Electronic address:
Copper-containing intrauterine devices (Cu-IUD) are adopted by worldwide women for contraception with the advantages of long-term effectiveness, reversibility and affordability. However, adverse effects occur in the initial implantation stage of Cu-IUD in uterine because of the burst release of Cu. To minimize the burst release, in this study, we designed a series of Cu-Fe alloys with 0.
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May 2024
Department of Metallurgical Engineering, Pukyong National University, 45 Yongso-ro, Nam-gu, Busan 48513, Republic of Korea.
Strain-controlled low cycle fatigue (LCF) tests were conducted on conventionally grained (CG) and ultrafine-grained (UFG) Al-Mg-Si alloys treated under various aging conditions. In the cyclic stress response (CSR) curves, CG peak-aged (PA) alloys showed initial cyclic hardening and subsequent saturation, whereas CG over-aged (OA) alloys displayed cyclic softening behavior close to saturation. The UFG materials exhibited continuous cyclic softening except for UFG 3; it originates from the microstructural stability of the UFG materials processed by severe plastic deformation (SPD).
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