DEENP - Artigos publicados em periódicos
URI permanente para esta coleçãohttp://www.hml.repositorio.ufop.br/handle/123456789/557
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Item Dry sliding wear features of an Al-20Sn-5Zn alloy affected by microstructural length scales.(2022) Cota, André Barros; Cruz, Clarissa Barros da; Botelho, Tamires; Silva, Maria Adrina Paixão de Souza da; Casteletti, Luiz Carlos; Garcia, Amauri; Cheung, NoéAl-Sn-Zn alloys are attractive options for use as wear-resistant materials. While Sn promotes self-lubricating characteristics, Zn strengthens the Al-rich matrix. Conventionally, the manufacturing of these alloys involves casting. However, there is still a paucity of studies that associate the solidification microstructure with the wear resistance of these alloys. Inspired by such considerations, this work aims at investigating the wear behavior of an Al-20Sn-5Zn [wt.%] alloy produced by a directional solidification technique. A set of samples with different microstructure length scales was subjected to ball cratering tests using a normal contact load of 0.25 N and six test times. The results show that the dependence of the wear behavior on the microstructure length scale becomes more expressive for longer sliding distances. It was found that coarser microstructures provide an improved wear resistance. In view of that, a possible spectrum of specific wear rates was determined as a function of the sliding distance, considering different microstructure length scales. Finally, experimental equations are proposed to represent a possible range of wear volume and wear coefficient according to the dendrite arm spacings.Item Solidification microstructure-dependent hydrogen generation behavior of AleSn and AleFe alloys in alkaline medium.(2021) Konno, Camila Yuri Negrão; Cruz, Clarissa Barros da; Costa, Thiago Antônio; Barros, André dos Santos; Goulart, Pedro Roberto; Garcia, Amauri; Cheung, NoéThis work deals with the development of quantitative correlations of hydrogen evolution performance with solidification microstructural and thermal parameters in Ale1Sn, Al e2Sn, Ale1Fe, and Al-1.5Fe [wt.%] alloys. The cellular growth as a function of growth and cooling rates is evaluated using power type experimental laws, which allow determining representative intervals of microstructure length scale for comparison purposes with the results of immersion tests in 5 wt%NaOH solution. For both Al alloys systems, hydrogen evolution becomes slower as the alloy solute content increased. However, for a given alloy composition, whereas a more homogeneous distribution of Sn-rich particles promotes faster hydrogen generation using AleSn alloys, coarsening of Al6Fe IMCs (intermetallic compounds) fibers favors hydrogen production using AleFe alloys. When solidification conditions that result in a range of cellular spacings within 16 and 19 mm are considered, the specific hydrogen production of the Al-1wt.%Fe alloy is higher than that of the other studied alloys.