Evolution of nano-pores during annealing of technically pure molybdenum sheet produced from different sintered formats
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in: International journal of refractory metals & hard materials, Jahrgang 110.2023, Nr. January, 106032, 01.2023.
Publikationen: Beitrag in Fachzeitschrift › Artikel › Forschung › (peer-reviewed)
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TY - JOUR
T1 - Evolution of nano-pores during annealing of technically pure molybdenum sheet produced from different sintered formats
AU - Jakob, Severin
AU - Lorich, Alexander
AU - Knabl, Wolfram
AU - Stark, Andreas
AU - Staron, Peter
AU - Clemens, Helmut
AU - Spörk-Erdely, Petra
N1 - Publisher Copyright: © 2022 The Authors
PY - 2023/1
Y1 - 2023/1
N2 - Molybdenum is a refractory metal with no phase transformation in the solid state and a high melting point. It is therefore an excellent structural material for various high temperature applications. Especially in this field of operation, significant creep resistance is essential. To achieve this, a microstructure with grains in the range of millimeters is desired. However, as demonstrated in the present study, the onset temperature for secondary recrystallization, which would lead to a beneficial grain size, is among other things dependent on the initial dimensions of the sintered part. One possible reason for the different microstructural evolutions is the influence of residual pores in sub-micrometer size. Sheets were thus fabricated via three different production routes employing the same initial Mo powder to exclude chemical variation as an influencing factor. The samples were investigated by in-situ small-angle X-ray scattering at a synchrotron radiation source with two different heating rates. Additionally, selected annealed samples were studied ex-situ with high energy X-rays. The apparent volume fraction of pores is compared to a volatilization model for the vaporization of typical accompanying elements and the induced thermal expansion.
AB - Molybdenum is a refractory metal with no phase transformation in the solid state and a high melting point. It is therefore an excellent structural material for various high temperature applications. Especially in this field of operation, significant creep resistance is essential. To achieve this, a microstructure with grains in the range of millimeters is desired. However, as demonstrated in the present study, the onset temperature for secondary recrystallization, which would lead to a beneficial grain size, is among other things dependent on the initial dimensions of the sintered part. One possible reason for the different microstructural evolutions is the influence of residual pores in sub-micrometer size. Sheets were thus fabricated via three different production routes employing the same initial Mo powder to exclude chemical variation as an influencing factor. The samples were investigated by in-situ small-angle X-ray scattering at a synchrotron radiation source with two different heating rates. Additionally, selected annealed samples were studied ex-situ with high energy X-rays. The apparent volume fraction of pores is compared to a volatilization model for the vaporization of typical accompanying elements and the induced thermal expansion.
UR - http://www.scopus.com/inward/record.url?scp=85140652824&partnerID=8YFLogxK
U2 - 10.1016/j.ijrmhm.2022.106032
DO - 10.1016/j.ijrmhm.2022.106032
M3 - Article
VL - 110.2023
JO - International journal of refractory metals & hard materials
JF - International journal of refractory metals & hard materials
SN - 0263-4368
IS - January
M1 - 106032
ER -