ELFT HÍRADÓ

[Zsolt Kovacs <kovacszs AT metal.elte.hu>]

                            MEGHIVO

                az ELTE TTK Anyagfizikai Tanszek
                        szeminariumara



           Prof. Pavel Lukac -Prof. Zuzanka Trojanova
              (Charles University, Czech Republic)

         Elastic and plastic behaviour of UFG magnesium


Helye: ELTE Fizikai Intezet, Anyagfizikai Tanszek
       1117 Budapest, Pazmany Peter setany 1/A, 4.emelet 4.52. terem

Ideje: 2006. oktober 24. kedd, 8.30.


Az eloadas rovid kivonata:

UFG Mg samples were prepared by milling procedure in an inert atmosphere 
and subsequent compacted and hot extruded. The linear grain size of 
specimens used was estimated by X-ray line profile analysis to be about 
100-150 nm. Internal friction spectrum was measured in the temperature 
interval RT-480°C. Two developed peaks in the internal friction spectrum 
were obtained at temperatures 103 °C and 358°C (1Hz). The influence of 
prestraining and subsequent annealing was observed on the low temperature 
peak. The activation energy of the both peaks was estimated to be 1.16 eV 
and 1.77 eV respectively. The activation volume has been estimated for low 
temperature peak. The low temperature peak has dislocation origin, while 
the high temperature peak is conditioned by the grain boundary sliding.

Compression testing was performed at temperatures from room temperature up 
to 300°C. Rapid decrease of the yield stress as well as the maximum 
stress with temperature was observed. This decrease and the flat character 
of the stress strain curves at elevated temperatures indicate possible 
contribution of (a) diffusion process/es and grain boundary sliding. 
Stress relaxation tests were conducted in order to analyse thermally 
activated processes occurring during plastic deformation.


Minden erdeklodot szivesen latunk.
A 2006/2007. tanev I. felevi programja megtalalhato a kovetkezo cimen:
http://metal.elte.hu


                                        Kovacs Zsolt