Cu-Ti Base Multicomponent Amorphous and Silver Nanocrystalline Composites

Jan M. Dutkiewicz ,  Wojciech Maziarz ,  Lidia Lityńska-Dobrzyńska ,  Łukasz Rogal ,  Tomasz Czeppe 

Polish Academy of Sciences, Institute of Metallurgy and Materials Sciences (IMIM PAN), Reymonta 25, Kraków 30-059, Poland

Abstract

Two easy glass forming alloys based on Cu-Ti binary system of compositions Cu47Ti33Zr11Ni8Si1 (alloy 1) and Ti50Cu20Ni25Co5 (alloy 2) were ball milled for 40 hours to obtain amorphous powders. X-ray diffraction studies confirmed complete amorphisation of both alloys after ball milling. Differential scanning calorimetry DSC measurements detected weak endothermal glass transition effects several degrees below the crystallization peaks at onset equal to 476oC for the alloy 1 and at 457oC for the alloy 2. However, high resolution transmission electron microscopy from powders allowed to identify fine intermatallic particles of a few nm in diameter within the amorphous matrix. Powders were then hot pressed at temperatures between the glass transition and crystallization in vacuum, to form bulk amorphous samples. DSC studies of hot pressed compacts confirmed presence of a similar heat effects as in the milled powders. Composites were prepared in the same way from mixed amorphous powders and nanocrystalline ball milled silver powder.  Various ratios of amorphous to nanocrystalline powder were applied with maximum of 60% of the nanocrystalline silver. The microhardness of the amorphous phase was higher than that of nanocrystalline silver and composites has shown lower compression strength than that of the amorphous samples, however of better ductility.

 

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Presentation: Oral at E-MRS Fall Meeting 2009, Symposium H, by Jan M. Dutkiewicz
See On-line Journal of E-MRS Fall Meeting 2009

Submitted: 2009-05-11 16:35
Revised:   2009-06-07 00:48