63 research outputs found
Synthesis of TiAl-based intermetallics with nanocrystalline structure by mechanical alloying and hot isostatic pressing: Microstructure stability and properties
No full textTwo fully dense nanocrystalline TiAl-based compacts, Ti-47.5Al-3Cr and Ti-48Al-2Nb-2Cr, were synthesized by hot isostatic pressing (HIP'ing) from mechanically alloyed (MA'd) powders. Microstructure evolution and phase transformations after MA'ing, HIP'ing, and following annealing were studied. Formation of amorphous phases was detected in both powders after 15 hour MA'ing. During HIP'ing, crystallization of the amorphous phases occurred and very fine equiaxed gamma-TiAl grains were formed. The grain size decreased when the temperature of HIP'ing was decreased, and it was 42 nm after HIP'ing at 725 °C. Grain growth occurred during annealing of the HIP'd alloys, which could be described by a single thermally activated process limited by a permanent pinning force. The activation energy of the grain growth was close to the activation energy for lattice diffusion of Ti in TiAl. Microhardness decreased with the annealing time and followed the Hall-Perch dependence on the grain size
Sinthesis of TiAl-Based Intermetallics with Nanocrystalline Structure by Mechanical Alloying and Hot Isostatic Pressing: Microstructure and Properties
No full textEffect of phase composition and hydrogen level on the deformation behavior of titanium-hydrogen alloys
No full textEffect of strain rate and temperature on the flow stress of β-phase titanium- hydrogen alloys
No full textAb Initio Molecular Dynamics Simulation of the Amorphous Structure of Ca-Mg-Cu and Ca-Mg-Zn Alloys (Preprint)
No full text
Ab Initio Molecular Dynamics Simulation of the Amorphous Structure of Ca-Mg-Cu and Ca-Mg-Zn Alloys
No full textDeveloping High Entropy Alloys for Nuclear Applications
No full textHigh entropy alloys (HEAs) were developed for their desirability of strength, hardness, and corrosion, wear, and radiation resistance. This makes them ideal for nuclear applications in advanced reactors. High entropy alloys are characterized as alloys containing at least 5 principal elements, each with an atomic percentage between 5 and 35% [1]. A process for fabrication and characterization of these alloys entails ball milling and spark plasma sintering (SPS), then characterization tools such as x-ray diffraction (XRD) and scanning electron microscopy (SEM).
[1] D. B. Miracle and O. N. Senkov, “A critical review of high entropy alloys and related concepts,” Acta materialia, vol. 122, pp. 448-511, 2017
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