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Structure and mechanical properties of ball milled TiAl-Cr intermetallics consolidated by hot pressing and pulse plasma sintering

Jan M. Dutkiewicz 2Andrzej Michalski 1Paweł Kurtyka 3Wojciech Maziarz 2

1. Warsaw University of Technology, Faculty of Materials Science and Engineering (InMat), Wołoska 141, Warszawa 02-507, Poland
2. Polish Academy of Sciences, Institute of Metallurgy and Materials Sciences (IMIM PAN), Reymonta 25, Kraków 30-059, Poland
3. Pedagogical Academy, Podchorążych 2, Kraków, Poland

Abstract

The TiAl-Cr alloys compositions were chosen from the g-phase stability region up to maximum 5 at. % chromium. The elemental powders were initially blended to desired composition of Ti-49,Al-49,Cr-2 and Ti-48,Al-47,Cr-5 (numbers indicate at. %). The ball milling process was performed in a high energy planetary mill Fritsch Pulverisette P/4 and detailed study of structure and micro-hardness changes during milling was described in [1].
Two consolidation methods of milled powders were applied: hot pressing at 1000C at 35MPa under argon flow and pulse plasma sintering. The conditions of latter method were optimized for pressure, voltage and pressure measuring temperature and shrinkage during the process. The micro-hardness of consolidated samples was about 860 HV1 and only small differences were observed between samples obtained by both methods. The mean density of pulse plasma sintered compact was about 98 % of theoretical while hot pressed samples had lower density close to 95% of theoretical. The TEM observation of consolidated samples revealed that pulse plasma sintered samples has a grain size in the range of tens of nanometers while the grains in the hot pressed samples are bigger and has size below 1 micron.
The compression tests performed in the temperature range between RT and 900C with deformation rate of 4x10-1s-1 demonstrated differences in ductility and strength of consolidated samples probably due to different level of densification and grains size.


[1] W. Maziarz, M. Fujda, L. Lityńska, J. Dutkiewicz, Microstructure and microhardness changes during ball milling of TiAlCr intermetallics, revived and accepted for publication in Proceeding of Advanced Materials and Technologies Conference, Łódź 2004, Poland

 

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Related papers

Presentation: oral at E-MRS Fall Meeting 2004, Symposium I, by Jan M. Dutkiewicz
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-05-20 14:13
Revised:   2009-06-08 12:55