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W G Marshall - One of the best experts on this subject based on the ideXlab platform.
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stress induced large curie temperature enhancement in fe 64 ni 36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the ${\text{Fe}}_{64}{\text{Ni}}_{36}$ Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
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stress induced large curie temperature enhancement in fe64ni36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the Fe{sub 64}N{sub 36}6 Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
P Gorria - One of the best experts on this subject based on the ideXlab platform.
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stress induced large curie temperature enhancement in fe 64 ni 36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the ${\text{Fe}}_{64}{\text{Ni}}_{36}$ Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
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stress induced large curie temperature enhancement in fe64ni36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the Fe{sub 64}N{sub 36}6 Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
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tensile stress dependence of the curie temperature and hyperfine field in fe zr b cu amorphous alloys
Physical Review B, 1996Co-Authors: J M Barandiaran, P Gorria, I Orue, M L Fdezgubieda, F Plazaola, A HernandoAbstract:FeZrB(Cu) metallic glasses present the same Invar (like) properties as the pure FeZr ones, in particular a large dependence of the Curie temperature on pressure. Magnetic and M\"ossbauer measurements show a decrease of the Invar character as the boron concentration increases, with a linear relationship between the change of Curie temperature per unit stress and the reciprocal of the Curie temperature itself. The influence of boron is shown to greatly enhance the weak itinerant ferromagnetism of FeZr glasses leading to stronger ferromagnetic behavior. \textcopyright{} 1996 The American Physical Society.
A Hernando - One of the best experts on this subject based on the ideXlab platform.
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stress induced large curie temperature enhancement in fe 64 ni 36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the ${\text{Fe}}_{64}{\text{Ni}}_{36}$ Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
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stress induced large curie temperature enhancement in fe64ni36 Invar alloy
Physical Review B, 2009Co-Authors: P Gorria, D Martinezblanco, Maria Jose Sanzo Perez, J A Blanco, A Hernando, Maria Angeles Lagunamarco, D Haskel, N M Souzaneto, Ronald I Smith, W G MarshallAbstract:We have succeeded in increasing up to 150 K the Curie temperature in the Fe{sub 64}N{sub 36}6 Invar alloy by means of a severe mechanical treatment followed by a heating up to 1073 K. The Invar behavior is still present as revealed by the combination of magnetic measurements with neutron and x-ray techniques under extreme conditions, such as high temperature and high pressure. The proposed explanation is based in a selective induced microstrain around the Fe atoms, which causes a slight increase in the Fe-Fe interatomic distances, thus reinforcing ferromagnetic interactions due to the strong magnetoelastic coupling in these Invar compounds.
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tensile stress dependence of the curie temperature and hyperfine field in fe zr b cu amorphous alloys
Physical Review B, 1996Co-Authors: J M Barandiaran, P Gorria, I Orue, M L Fdezgubieda, F Plazaola, A HernandoAbstract:FeZrB(Cu) metallic glasses present the same Invar (like) properties as the pure FeZr ones, in particular a large dependence of the Curie temperature on pressure. Magnetic and M\"ossbauer measurements show a decrease of the Invar character as the boron concentration increases, with a linear relationship between the change of Curie temperature per unit stress and the reciprocal of the Curie temperature itself. The influence of boron is shown to greatly enhance the weak itinerant ferromagnetism of FeZr glasses leading to stronger ferromagnetic behavior. \textcopyright{} 1996 The American Physical Society.
Stephen C Veldhuis - One of the best experts on this subject based on the ideXlab platform.
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density and mechanical properties in selective laser melting of Invar 36 and stainless steel 316l
Journal of Materials Processing Technology, 2019Co-Authors: Mostafa Yakout, M A Elbestawi, Stephen C VeldhuisAbstract:Abstract In this study, the process-structure-property relationship for selective laser melting of Invar 36 and stainless steel 316L is discussed. Invar 36 and stainless steel 316L have been used in various industrial applications for their unique properties, especially in the aerospace industry. Invar 36 offers a very low coefficient of thermal expansion while stainless steel 316L offers high corrosion resistance. Since both materials are weldable, but hard to machine, this study is aimed at finding the optimum laser process parameters for producing dense components from both alloys. A full factorial design of experiments was formulated in this paper to study a wide range of process parameters for both materials. The bulk density, tensile mechanical properties, fractography, material composition, and residual stresses of the parts produced were investigated. An optimum process window has been suggested based on experimental work. The induced residual stresses were categorized into two categories: microscopic residual stresses and macroscopic residual stresses. The microscopic residual stresses were measured using X-ray diffraction method and the macroscopic residual stresses were measured using cantilever deflection method and finite element simulations. The paper proposes two laser energy densities for each material: brittle-ductile transition energy density, ET, and critical laser energy density, EC. Below the brittle-ductile transition energy density, the parts exhibited void formation, low density, and brittle fracture. Above the critical energy density, the parts showed vaporization of some alloying elements that have low boiling temperatures. Stable melting ranges were found to occur between these two laser energy densities: 52.1–86.8 J/mm3 for Invar 36 and 62.5–104.2 J/mm3 for stainless steel 316L.
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a study of thermal expansion coefficients and microstructure during selective laser melting of Invar 36 and stainless steel 316l
Additive manufacturing, 2018Co-Authors: Mostafa Yakout, M A Elbestawi, Stephen C VeldhuisAbstract:Abstract This paper presents an experimental study on the metallurgical issues associated with selective laser melting of Invar 36 and stainless steel 316 L and the resulting coefficient of thermal expansion. Invar 36 has been used in aircraft control systems, electronic devices, optical instruments, and medical instruments that are exposed to significant temperature changes. Stainless steel 316 L is commonly used for applications that require high corrosion resistance in the aerospace, medical, and nuclear industries. Both Invar 36 and stainless steel 316 L are weldable austenitic face-centered cubic crystal structures, but stainless steel 316 L may experience chromium evaporation and Invar 36 may experience weld cracking during the welding process. Various laser process parameters were tested based on a full factorial design of experiments. The microstructure, material composition, coefficient of thermal expansion, and magnetic dipole moment were measured for both materials. It was found that there exists a critical laser energy density for each material, EC, for which selective laser melting process is optimal for material properties. The critical laser energy density provides enough energy to induce stable melting, homogeneous microstructure and chemical composition, resulting in thermal expansion and magnetic properties in line with that expected for the wrought material. Below the critical energy, a lack of fusion due to insufficient melt tracks and discontinuous beads was observed. The melt track was also unstable above the critical energy due to vaporization and microsegregation of alloying elements. Both cases can generate stress risers and part flaws during manufacturing. These flaws could be avoided by finding the critical laser energy needed for each material. The critical laser energy density was determined to be 86.8 J/mm3 for Invar 36 and 104.2 J/mm3 for stainless steel 316 L.
Mostafa Yakout - One of the best experts on this subject based on the ideXlab platform.
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in situ monitoring and detection of spatter agglomeration and delamination during laser based powder bed fusion of Invar 36
Optics and Laser Technology, 2021Co-Authors: Mostafa Yakout, Ian Phillips, Mo Elbestawi, Qiyin FangAbstract:Abstract Invar 36 (FeNi36) is a weldable nickel alloy, known for its low thermal expansion properties, that contains 36% of nickel and 64% iron. The laser-based powder bed fusion process is often associated with defects and flaws that should be controlled for production quality. Spatter formation and delamination are two phenomena that could be observed in thermal images taken during the laser melting process. This paper presents an in-situ monitoring setup for detecting spatters and delamination of Invar 36. The size, shape, count, and cooling rate of spatter particles are evaluated using a combination of infrared pyrometer and high-speed infrared thermography. Thermograms of Invar 36 are processed to determine the spatter characteristics. The influence of processing conditions on the spatter count, spatter size, and size of melt track is discussed. The effect of spatters on the surface morphology of Invar 36 parts is also investigated. The processing conditions that cause melt pool instabilities, excessive spattering, and delamination are presented. This paper concludes recommendations for avoiding delamination and excessive spatter formation during the laser-based powder bed fusion of Invar 36.
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density and mechanical properties in selective laser melting of Invar 36 and stainless steel 316l
Journal of Materials Processing Technology, 2019Co-Authors: Mostafa Yakout, M A Elbestawi, Stephen C VeldhuisAbstract:Abstract In this study, the process-structure-property relationship for selective laser melting of Invar 36 and stainless steel 316L is discussed. Invar 36 and stainless steel 316L have been used in various industrial applications for their unique properties, especially in the aerospace industry. Invar 36 offers a very low coefficient of thermal expansion while stainless steel 316L offers high corrosion resistance. Since both materials are weldable, but hard to machine, this study is aimed at finding the optimum laser process parameters for producing dense components from both alloys. A full factorial design of experiments was formulated in this paper to study a wide range of process parameters for both materials. The bulk density, tensile mechanical properties, fractography, material composition, and residual stresses of the parts produced were investigated. An optimum process window has been suggested based on experimental work. The induced residual stresses were categorized into two categories: microscopic residual stresses and macroscopic residual stresses. The microscopic residual stresses were measured using X-ray diffraction method and the macroscopic residual stresses were measured using cantilever deflection method and finite element simulations. The paper proposes two laser energy densities for each material: brittle-ductile transition energy density, ET, and critical laser energy density, EC. Below the brittle-ductile transition energy density, the parts exhibited void formation, low density, and brittle fracture. Above the critical energy density, the parts showed vaporization of some alloying elements that have low boiling temperatures. Stable melting ranges were found to occur between these two laser energy densities: 52.1–86.8 J/mm3 for Invar 36 and 62.5–104.2 J/mm3 for stainless steel 316L.
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a study of thermal expansion coefficients and microstructure during selective laser melting of Invar 36 and stainless steel 316l
Additive manufacturing, 2018Co-Authors: Mostafa Yakout, M A Elbestawi, Stephen C VeldhuisAbstract:Abstract This paper presents an experimental study on the metallurgical issues associated with selective laser melting of Invar 36 and stainless steel 316 L and the resulting coefficient of thermal expansion. Invar 36 has been used in aircraft control systems, electronic devices, optical instruments, and medical instruments that are exposed to significant temperature changes. Stainless steel 316 L is commonly used for applications that require high corrosion resistance in the aerospace, medical, and nuclear industries. Both Invar 36 and stainless steel 316 L are weldable austenitic face-centered cubic crystal structures, but stainless steel 316 L may experience chromium evaporation and Invar 36 may experience weld cracking during the welding process. Various laser process parameters were tested based on a full factorial design of experiments. The microstructure, material composition, coefficient of thermal expansion, and magnetic dipole moment were measured for both materials. It was found that there exists a critical laser energy density for each material, EC, for which selective laser melting process is optimal for material properties. The critical laser energy density provides enough energy to induce stable melting, homogeneous microstructure and chemical composition, resulting in thermal expansion and magnetic properties in line with that expected for the wrought material. Below the critical energy, a lack of fusion due to insufficient melt tracks and discontinuous beads was observed. The melt track was also unstable above the critical energy due to vaporization and microsegregation of alloying elements. Both cases can generate stress risers and part flaws during manufacturing. These flaws could be avoided by finding the critical laser energy needed for each material. The critical laser energy density was determined to be 86.8 J/mm3 for Invar 36 and 104.2 J/mm3 for stainless steel 316 L.
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the selection of process parameters in additive manufacturing for aerospace alloys
The International Journal of Advanced Manufacturing Technology, 2017Co-Authors: Mostafa Yakout, M A Elbestawi, Andrea Cadamuro, S C VeldhuisAbstract:Invar 36 has gained considerable popularity in many industries, including the aerospace industry, because of its low coefficient of thermal expansion. In this paper, a brief overview for the research needs in metal additive manufacturing is presented. A thorough study for the influence of process parameters on the quality of the parts produced is presented. This study is beneficial for the long-term growth of the additive manufacturing industry. The paper aims to select the process parameters that can be used to fabricate dense parts from Invar 36 (UNS K93600) using the selective laser melting process. In this research, a group of cubes was fabricated using different process parameters from Invar 36 powder using a selective laser melting machine. The density, microstructures, and surface features of these cubes were measured. Experimental observations were drawn from the results of the preliminary analyses. The influence of the process parameters on the density of the parts produced is discussed in this paper.
