KMITL

Permanent URI for this communityhttps://dspace.kmitl.ac.th/handle/123456789/1

Browse

Settings

Subject: search.filters.subject.Structure refinement

Search Results

Now showing 1 - 3 of 3
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Improvement in the Uniformity of Bismuth Distribution in an Al-Bi Alloy by Ultrasonic Processing and Hydrogen Melt Enrichment
    (2026-01-01)
    Chankitmunkong, Suwaree
    ;
    Eskin, Dmitry G.
    ;
    Diewwanit, Onnjira
    Manufacturing of immiscible metallic alloysMetallic alloys, such as aluminumAluminum-bismuth, faces challenges in achieving uniform distribution of secondary phase droplets/particles due to their higher density and tendency to agglomerate/coalesce, which negatively affects mechanical propertiesMechanical properties. Recent studies on emulsification of immiscible liquids showed that ultrasonic treatment (UST) of gas-saturated systems improved the droplet distribution. In this work we tested this approach on Al-Bi alloys with melts saturated with hydrogenHydrogen. It was demonstrated that this combination resulted in the uniform distribution of fineFines Bi droplets in the aluminumAluminum matrix. UST had a dual role in the process: (a) increased cavitation facilitated by dissolved hydrogenHydrogen improved the efficiency of droplet formation and distribution and (b) ultrasonic degassing eliminated the adverse effects of gas porosity. Finer and evenly distributed Bi particles enhanced the wear resistance of the alloy.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Enhancing the properties of a hypereutectic Al-Fe alloy through recycled aluminum scrap and ultrasonic melt processing
    (2025-10-01)
    Tangsuksan, Tawatchai
    ;
    Pandee, Phromphong
    ;
    Diewwanit, Onnjira
    ;
    Limmaneevichitr, Chaowalit
    ;
    Tyurnina, Anastasia V.
    This paper focuses on the effects of using recycled aluminum beverage cans and ultrasonic melt processing (USP) on the microstructure and properties of a hypereutectic Al-Fe alloy that has potential in structural and electric applications. The proportion of recycled aluminum scrap used as the starting material varied, and its influence on grain refinement, intermetallic phase formation, precipitation hardening, and mechanical performance was examined. Ultrasonic melt processing (USP) was applied to refine the microstructure and improve phase distribution. The experimental results showed that both the addition of recycled aluminum scrap and USP significantly increased the hardness and tensile strength of the alloys, with further improvements observed after optimal aging treatments, although ductility slightly decreased. Additionally, the presence of alloying elements from the recycled scrap, such as Mg, Mn, Si, and Cu, led to a reduction in electrical conductivity while improving the precipitation hardening response. This study highlights the potential of using recycled materials and advanced processing techniques to develop sustainable, high-performance aluminum alloys for various industrial applications.
  • Loading...
    Thumbnail Image
    Some of the metrics are blocked by your 
    consent settings
    Item type:Publication,
    Structural, optical and electrical properties of the microcrystalline structure of (Ba1-xY2x/3)(Zr0.20Ti0.80)O3 ceramics
    (2020-07-01)
    Sumang, Rattiphorn
    ;
    Thongmee, Navavan
    ;
    Bongkarn, Theerachai
    ;
    Prasertpalichat, Sasipohn
    ;
    Kidkhunthod, Pinit
    Yttrium (Y<sup>3+</sup>) doped barium zirconate titanate, (Ba<inf>1-x</inf>Y<inf>2x/3</inf>)(Zr<inf>0.20</inf>Ti<inf>0.80</inf>)O<inf>3</inf>; BYZT ceramics with varying x (0 = x ≤ 0.10) were prepared by the solid-state reaction method. These samples were analyzed by X-ray diffraction (XRD) and the XRD patterns were fitted using the Rietveld refinement. The local structural changes of the BYZT ceramics were investigated by synchrotron X-ray absorption spectroscopy. The results showed that an increase in the x content in the BYZT lattice structure significantly affected the phase transition behavior and the local structure around the Ti absorbing atoms, which corresponds with the phase transition from a tetragonal to a cubic structure. SEM images showed a uniform and highly dense microstructure with increasing x values. The optical band gap (E<inf>gap</inf>) values measured from the UV–visual diffuse reflectance spectra, showed a decrease from ~3.55 eV to ~2.90 eV with increasing values of x. The modified Curie-Weiss law showed that a normal ferroelectric phase transition is observed in the unmodified BZT ceramic and as the concentration of x increased, it induces diffuseness in the phase transition behavior. The largest dielectric constant (ε<inf>r</inf> = 13,200), the highest recoverable energy-storage density (W<inf>rec</inf> = 1.76 J/cm<sup>3</sup>) with an excellent energy storage efficiency (η = 91%) under a lower electric field of 50 kV/cm and lowest dielectric loss (tanδ = 0.01) were found in the composition of Ba<inf>0.98</inf>Y<inf>0.01337</inf>Zr<inf>0.2</inf>Ti<inf>0.8</inf>O<inf>3</inf> (x = 0.02 mol.%).