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M. Guzmán

Bio: M. Guzmán is an academic researcher from University of Concepción. The author has contributed to research in topics: Hot pressing & Powder metallurgy. The author has an hindex of 1, co-authored 2 publications receiving 3 citations.

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TL;DR: The alloying process was carried out in stainless steel containers during 6 or 8 h of milling, under argon atmosphere, and the ball to powder charge ratio was 5:1 as mentioned in this paper.
Abstract: Copper powder of 140 μm mean size was mechanical alloyed with several compounds, 2 % B 4 C, 2 % ZrC, 1 % CrB, 2 % Cr 3 C 2 , 1 and 2 vol % ZrB 2 in a RETSCH PM high energy balls mill The alloying process was carried out in stainless steel containers during 6 or 8 h of milling, under argon atmosphere, and the ball to powder charge ratio was 5:1 Instead of HIP processing, the alloyed powders were consolidated by uniaxial hot pressing at 650 °C for 2 h at a pressure of 90 MPa in argon atmosphere Afterward the compact samples of 30 x 10 x 10 mm were hot rolled at 850 °C with area reduction from 10 to 40 % If an homogeneous hot pressing process is obtained, the subsequent hot rolling can be avoided as only an annealing effect is produced, characterized by a small decrease in hardness and tensile strength with a small increase in ductility

2 citations


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TL;DR: In this paper, the effect of milling process on microstructure and mechanical properties observed has been related to the collection of iron, chromium, carbon and oxygen, with Fe-Cr oxicarbides and cuprospinel particles of size about 5-15 nm, which are precipitated during hot consolidation.
Abstract: The dispersion strengthened copper alloys obtained by mechanical alloying (MA) followed by elevated temperature treatment are attractive due to their excellent combination of thermal and electrical conductivities, strength and microstructural stability. The strengthening of pure copper is provided by mechanical milling with 0.5% of ZrB2 and 1 or 0.5 vol.% of ZrC as fine dispersants. The alloyed powders are hot consolidated by an uniaxial pressing at 923 K and rolling with a 25% of reduction at 1073 K. Microstructural characterization of consolidated samples are by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The hot consolidation process resulted in fully dense MMCs materials with an adequate tensile strength as high as 650 MPa and electrical conductivity up to 48% IACS. The effect of milling process on microstructure and mechanical properties observed has been related to the collection of iron, chromium, carbon and oxygen, with Fe-Cr oxicarbides and cuprospinel particles of size about 5-15 nm, which are precipitated during hot consolidation. The electron microscopy studies revealed that the strength of consolidated metal matrix composites, Copper-Zirconium ceramics are consistent with approximations based on Orowan and Hall-Petch strengthening mechanisms. (© 2007 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)

7 citations

Journal ArticleDOI
TL;DR: In this paper, copper powder was mechanically alloyed with lithium (purity>99%) in a SPEX ball mill for 15 h under an argon atmosphere using WC containers and stainless steel balls, and the alloyed powders were then hot-consolidated by uniaxial hot pressing at different temperatures (300, 400, 500, and 550 °C).

5 citations

Journal ArticleDOI
TL;DR: Lab results demonstrated that E. nitens plywood satisfies all the British Standard Institution requirements for exterior use and bonding quality in solid wood of juvenile (11 years) E. Nitens.
Abstract: SUMMARY This work evaluates the bonding quality in solid wood of juvenile (11 years) E. nitens. Edge-glued panels were manufactured and bonded with PVA (Polyvinyl acetate). The mechanical properties of the panels were determined and compared with those of mature (25 years) P. radiata panels. Shear strength values in E. nitens panels were found to be 35% higher than P. radiata panels according to British Standard EN 204-205 on non-structural adhesives for wood joining. Juvenile E. nitens wood venners were used to manufacture exterior ‐grade plywood panels. Laboratory results demonstrated that E. nitens plywood satisfies all the British Standard Institution requirements for exterior use.

1 citations