SIPS 2018

DETAILLED PROGRAM OVERVIEW

Microstructure-related Issues for Miniaturized Tensile Tests
Jan Dzugan¹; Libor Kraus¹; Miroslava Sindelarova¹; Karel Sperlink¹;
¹COMTES FHT INC., Dobrany, Czech Republic;
PAPER: 106/Iron/Plenary (Oral)
SCHEDULED: 11:20/Tue./Mar Azul (50/1st)

ABSTRACT:
Mechanical characterization of construction materials is a fundamental step to enabling reliable design. Globally, many standards in the field of mechanical characterization have been developed. With improving FEM simulations and material models, the local properties and anisotropies become very interesting, as they can be implemented in FEM simulations. However, data on local properties should be provided based on so fan no-standard miniaturized specimens providing information for specific locations/orientation to feed material models. With specimens downsizing there are consequently many issues, such as geometrical similarity between standard and miniaturized specimens and probably the main one, the microstructure. As the miniaturized specimens for engineering applications should still be related to bulk material behavior, some critical number of grains should be within the volume of the specimens gauge section in order to represent polycrystal behavior. This paper deals with the investigation of grain size influence on tensile behavior determined with the use on miniaturized tensile specimens with gauge section thickness of 0.5mm. Tensile tests are a very basic test in the field of mechanical properties characterization, and specimens downsizing can be seen in many papers nowadays, eg. (1-2). It has been proven that the performance of miniaturized tensile tests in comparison to standard ones is very good. In order to set the boundaries up to which it is possible to go regarding the specimens cross section and maintain comparability with standard sized specimens, the grain size influence is investigated here. Two steels with several different grains sizes are investigated here. Various grain sizes were obtained by heat treatment, resulting in a wide range of the grain sizes. Tensile tests of standard specimens and miniaturized ones are carried out on the investigated heats of steels for comparison. The results obtained here point out that very good performance of miniaturized tensile tests in terms of providing information on "bulk" material behavior can be achieved, even with very few grains over the specimen's thickness.

References:
[1] Džugan, J., Prochazka, R., Konopik, P.: Micro-tensile test technique development and application to mechanical property determination, ASTM Special Technical Publication STP 1576, 2015, pp. 12-30.
[2] Gussev, M.N., Busby, J.T., Field, K.G., Sokolov, M.A., Gray, S.E.: Role of scale factor during tensile testing of small specimens, 2015, ASTM Special Technical Publication STP 1576, pp. 31-49.