Browsing by Subject "Ball milling"
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Item Open Access Phase transformation during mechano-synthesis of nanocrystalline/amorphous Fe–32Mn–6Si alloys(Elsevier, 2013) Amini, R.; Shamsipoor, A.; Ghaffari, M.; Alizadeh, M.; Okyay, Ali KemalMechano-synthesis of Fe-32Mn-6Si alloy by mechanical alloying of the elemental powder mixtures was evaluated by running the ball milling process under an inert argon gas atmosphere. In order to characterize the as-milled powders, powder sampling was performed at predetermined intervals from 0.5 to 192 h. X-ray florescence analyzer, X-ray diffraction, scanning electron microscope, and high resolution transmission electron microscope were utilized to investigate the chemical composition, structural evolution, morphological changes, and microstructure of the as-milled powders, respectively. According to the results, the nanocrystalline Fe-Mn-Si alloys were completely synthesized after 48 h of milling. Moreover, the formation of a considerable amount of amorphous phase during the milling process was indicated by quantitative X-ray diffraction analysis as well as high resolution transmission electron microscopy image and its selected area diffraction pattern. It was found that the α-to-γ and subsequently the amorphous-to-crystalline (especially martensite) phase transformation occurred by milling development.Item Open Access Quantitative phase evolution during mechano-synthesis of Ti-Ni-Cu shape memory alloys(Elsevier, 2012-05-29) Amini, R.; Alijani, F.; Ghaffari, M.; Alizadeh, M.; Okyay, Ali KemalTi-41Ni-9Cu shape memory alloy was synthesized by mechanical alloying of pure elemental Ti, Ni, and Cu powders using high-energy ball milling. The qualitative and quantitative phase analyses of the as-milled powders were done by X-ray diffraction (XRD) using Rietveld refinement and the alloys microstructure was studied by scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Concerning the results, by milling evolution, the dissolution of the primary materials occurred at different rates and a considerable amount of the amorphous phase as well as B19′-martensite and B2-austenite was created. The formation of Ni solid solution was also evidenced prior to its dissolution. It was found that at sufficient milling time, the mechano-crystallization of the amorphous phase occurred and at the end of milling, the B19′-martensite is the dominant phase of the structure.