The influence of orientation of single crystals with different stacking fault energy on deformation texture formation during drawing

No.: 2016/21/B/ST8/01183
Program: OPUS11
Financing unit: NCN
Project leader: professor Jarosław Mizera
Function: leader
Timeframe: 2017-2020
 

Objective of the conducted studies

The objective of the project is to characterize the essential mechanisms for the creation and shaping of a deformation texture in materials with a regularly face-centered structure (A1) undergoing the process of drawing. Strongly non-linear dependence of the formation or disappearance of fibrous texture type <001> and <111> depending on the stacking fault energy has not been explained in the literature to date. In the project, through the examination of changes the orientation of single crystals of different orientations and EBU, a qualitative and quantitative model of active deformation mechanisms involved in the formation of texture will be created. The above description will allow to initiate a discussion on the evolution of individual texture components during the process of drawing and will form a significant contribution to the modeling of texture of materials subjected to complex states of deformation.
 

Test method/methodology

In the experimental part of the project the tests will focus on the use of techniques for the assessment of changes and evolution of the microstructure and texture of various monocrystals with A1 lattice after the drawing process. For that purpose, the following techniques will be utilized:

1. Light microscopy (LM), transmission electron microscopy (TEM) or scanning transmission electron microscopy (STEM) - Observations using light microscopy (LM) in order to analyze the heterogeneity of deformation in the deformed metal macroscopically. Use of research techniques TEM and STEM in order to assess the changes at the microstructural level. In the case of materials with low and medium EBU, description of the formation of deformation bands, twins and local dislocation density changes. An attempt at estimating, based on the twin forming criterion or critical stress, when the twin system gains the possibility to activate and referring the obtained data to changes in the texture in the given scope of deformations.
2. Hardness measurements. Performance of microhardness samples on two cross sections of the analyzed samples in order to demonstrate the changes and differences in mechanical properties.
3. EBSD or t-EBSD methodology. Determination of the impact of the applied deformation on the formation of low and high angle grain boundaries. Comparison of the effect of orientation and EBU on the evolution of the microstructure and local texture of sub-grains after deformation. Compilation of the obtained data with qualitative and quantitative data as a result of measurements of the texture through X-ray.
4. X-ray texture analysis (XRD) of materials after the drawing process. Qualitative and quantitative analysis of texture components resulting from deformation. Determination of the relationship between the EBU and the texture/initial orientation of RSC materials and components of the texture formed as a result of the drawing process.
    

Impact of the expected results on the development of science, civilization, society

During a literature review relating to the formation of texture and microstructure as a result of deformation of metals with crystal lattice A1 in the drawing process it was noted that the topic has not been clarified. It is known that as a result of the imposed deformation, a dual fiber texture <111> and <001> of different volume fraction is formed in the materials. No information was found as to what influence there was of initial orientation on the formation of texture after the drawing process. There is also a lack of information on the differences that may occur at the microstructure level in similarly deformed single crystals with various orientation. This project is an attempt to complement the research.