New possibilities of achieving ultra - fine grained microstructure in metals and alloys employing MaxStrain technology

Roman M. Kuziak 1Wladyslaw Zalecki 1Maciej Pietrzyk 2Stanisław Węglarczyk 2

1. Institute for Ferrous Metallurgy (IMZ), Karola Miarki, Gliwice 44-100, Poland
2. AGH University of Science and Technology (AGH), al. Mickiewicza 30, Kraków 30-059, Poland

Abstract

In the paper, the deformation experiments conducted on the MaxStrain system aimed at achieving ultra fine grained structure in selected metals and alloys are described. The MaxStrain system provides an alternative way of developing such a structure compared to other methods that involve the effect of severe plastic deformation on grain refinement in bulk samples, such as the equal channel angular pressing. The part of the sample (10 mm in length) is compressed by two synchronised anvils to maintain its integrity. The sample is rotated by 90 degrees between the consecutive deformations, and it may be allowed to expand along its axis during deformation or may be restrained at the ends requiring the lateral deformation in the deformation zone. In this way, a total strain of 20 can be accumulated in the structure causing a substantial grain refinement.

In the experiments, the samples were cold deformed 10, 20 and 40 times with constant strain (0.2, 0.4 and 0.6) for all deformations. Constant strain rate of 1/s was applied for all deformation schedules.

The deformed structure of the samples was investigated by means of the Light and Transmission Electron Microscopy. Also, the hardness measurement in the deformed zone was conducted. The mean grain size of the samples was around 150 nm, and the hardness tripled in the samples compared to the annealed characterised be a large grain size material.

The microstructure and hardness of the samples deformed employing MaxStrain system are comparable to the ones obtained in the samples deformed using equal channel angular pressing. However, the MaxStrain technology is more flexible compared to the other methods of plastic working in terms of the deformation parameters. Also, MaxStrain system allows sophisticated heat treatment operations to be applied during and after the deformation sequence.





Related papers
  1. Recrystallization and Grain Growth in Nano-structured Austenitic Stainless Steel under Electric Current Heating
  2. The application of thermodynamic calculations for the semi-solid processing design

Presentation: oral at E-MRS Fall Meeting 2003, Symposium G, by Roman M. Kuziak
See On-line Journal of E-MRS Fall Meeting 2003

Submitted: 2003-05-23 12:53
Revised:   2009-06-08 12:55
Google
 
Web science24.com
© 1998-2018 pielaszek research, all rights reserved Powered by the Conference Engine