Papers by Joakim Nordström
Linköping studies in science and technology. Thesis, Jun 12, 2024
Materials science and engineering. A, Structural materials: proporties, microstructures and processing/Materials science & engineering. A, Structural materials: properties, microstructure and processing, Apr 1, 2024
steel research international
The main purpose with this investigation was to clarify when or if specific grades will soften or... more The main purpose with this investigation was to clarify when or if specific grades will soften or harden during the straightening process in a seven roll cross roll straightening machine. The aim was solely made to include tubes which had been cold worked to achieve high yield strength levels. The straightening process will induce lengthwise tensile and compressive stress and strain. According to theory straightening could therefore also induce considerable Bauschinger effect. Physical tests, with material from pilgered tubes, in a laboratory environment were performed to give a well-defined set up of the strain levels and sign of the same. Real in process trials were also performed. Parallel to the physical laboratory tests and the real process tests a FEM-simulation and a FEM-model to calculate strain levels was developed. Two material types were investigated, but the results are only unambiguous for material A. Further investigations need to be done on material B to give a clea...
Procedia Structural Integrity, 2019
Materials Science Forum
Deformation twinning behaviors have been studied in high Ni alloys, Alloy 28 or Sanicro 28 and Al... more Deformation twinning behaviors have been studied in high Ni alloys, Alloy 28 or Sanicro 28 and Alloy 625 at RT and at cryogenic temperature. The microstructures were evaluated using SEM-EBSD. Some constitutive approach has also been used in the discussion on the deformation twinning in high Ni-alloys. The results show that deformation twinning can occur in high Ni alloys depending on the chemical composition, strain range and stress conditions. TWIP can occur in the Ni based superalloy Alloy 625 at cryogenic temperature, which increases both strength and ductility. This is the first report of this phenomena for this alloy. Deformation twinning in high Ni alloys occurs heterogeneously in the material, depending on crystallographic parameters such as grain orientation and Schmid factor. Formation of deformation twins can lead to high texture in the material, which will contribute to the increase of strength. The mechanisms for the formation of deformation twins in high Ni alloys have ...
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Papers by Joakim Nordström