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Hao Z.H.,State Key Laboratory of Powder Metallurgy | Sun W.,State Key Laboratory of Powder Metallurgy | Xiong X.,State Key Laboratory of Powder Metallurgy
Materials Research Innovations | Year: 2014

Carbon/carbon (C/C) composites were doped by Zr and Zr2Cu respectively. The microstructures and ablation properties of two kinds of doped C/C composites were compared. The results indicate that the sweat cooling effect of Cu phase can improve the antiablation properties of the C/C-ZrC composites when Zr2Cu was used as the infiltrator. © W. S. Maney & Son Ltd. 2014.

Lei Q.,Central South University | Li Z.,Central South University | Li Z.,State Key Laboratory of Powder Metallurgy | Xiao T.,Central South University | And 4 more authors.
Intermetallics | Year: 2013

A new ultrahigh strength Cu-6.0 Ni-1.0 Si-0.5 Al-0.15 Mg-0.1 Cr alloy has been developed by alloying design and thermal mechanical treatment. Electrical conductivity, mechanical properties of the designed alloy such as hardness, tensile strength, yield strength, elongation and anti-stress relaxation resistance were tested. The mechanical properties and electrical properties of designed alloy were comparable to those of Cu-Be alloys, and its anti-stress relaxation resistance even was better than that of Cu-Be alloys at evaluated temperature. Microstructure observation revealed that β-Ni3Si phase precipitated in the initial stages ageing process, with further increasing the ageing time, β-Ni3Si, and δ-Ni2Si phase precipitates appeared and contributed to the ultrahigh strength by Orowan strengthening. The satellites spots around diffraction spots of Cu matrix symmetrically in [112]Cu zone crystal axis have been determined, resulting that satellites spots are from the electron diffraction of δ-Ni2Si precipitates. The crystal orientation relationship between matrix and precipitates is that: (111̄)cu//( 111̄)β//(02̄1)δ;[112]cu// [112]β//[012]δ. © 2013 Elsevier Ltd. All rights reserved.

Li X.,Central South University | Duan Y.L.,Central South University | Xu G.F.,Central South University | Xu G.F.,State Key Laboratory of Powder Metallurgy | And 4 more authors.
Materials Characterization | Year: 2013

This work presents the use of a mechanical testing system and the electron backscatter diffraction technique to study the mechanical properties and twinning systems of cold-rolled commercial purity titanium, respectively. The dependence of twinning on the matrix orientation is analyzed by the distribution map of Schmid factor. The results showed that the commercial purity titanium experienced strong strain hardening and had excellent formability during rolling. Both the 112̄2 <112̄3̄> compressive twins and 101̄2 <101̄1̄> tensile twins were dependent on the matrix orientation. The Schmid factor of a grain influenced the activation of a particular twinning system. The specific rolling deformation of commercial purity titanium controlled the number and species of twinning systems and further changed the mechanical properties. © 2013 Elsevier Inc.

Li H.Z.,Central South University | Li H.Z.,State Key Laboratory of Powder Metallurgy | Wang H.J.,Central South University | Li Z.,Central South University | And 2 more authors.
Materials Science and Engineering A | Year: 2010

Compression tests of Mg-10Gd-4.8Y-2Zn-0.6Zr alloy have been performed in the compression temperature range from 350°C to 500°C and the strain rate range from 0.001s-1 to 1s-1. The flow behavior has been investigated by the stress-strain behavior and dynamic recrystallization (DRX) behavior. The critical condition and the kinetics of DRX of the alloy deformed at the temperature of 500°C and the strain rate of 0.01s-1 were determined. The processing maps at different strains were established, which illustrated that the processing maps of the alloy was sensitive to strains. The optimum parameters for hot working of the alloy has been determined according to the processing map and microstructure at the true strain of 0.7, and that was the deformation temperature of 500°C and the strain rate of 0.01s-1. © 2010 Elsevier B.V.

Xiao Z.,Central South University | Xiao Z.,University of Liverpool | Li Z.,Central South University | Li Z.,State Key Laboratory of Powder Metallurgy | And 6 more authors.
Corrosion Science | Year: 2013

A novel gold-imitation copper alloy (CuZnAlNiSnBRe) was designed and its corrosion behavior in salt spray environment was investigated. The new alloy has better tarnish resistance and corrosion resistance than the current coinage alloy used in China (H7211). A multi-layer film formed on the surface of the new alloy after a period of exposure to salt spray was responsible for the good resistance of the alloy. The corrosion products were a mixture of CuO, Cu2O, ZnO, Al2O3 and Al(OH)3, with the transition from Cu2O to CuO occurring during the corrosion process. © 2013 Elsevier Ltd.

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