Bart Prorok - Academia.edu (original) (raw)
Papers by Bart Prorok
Smithells Metals Reference Book, 2004
Metallic materials that are outside the mainstream of conventional metals and alloys, with respec... more Metallic materials that are outside the mainstream of conventional metals and alloys, with respect to composition, structure and/or processing, are discussed in this chapter.
Conference Proceedings of the Society for Experimental Mechanics Series, 2013
A new method of accurately and reliably extract the actual Young's modulus of a thin film on a su... more A new method of accurately and reliably extract the actual Young's modulus of a thin film on a substrate has been developed. The method is referred to as the discontinuous elastic interface transfer model. The method has been shown to work exceptionally well with films and substrates encompassing a wide range of elastic moduli and Poisson ratios. The advantage of the method is that it does not require a continuous stiffness method and can use the standard Oliver and Pharr analysis and the use of a predictive formula for determining the modulus of the film as long as the film thickness, substrate modulus and bulk Poisson ratio of the film are known. However, when there is much pileup during the indentation process in a softer film, the experimental data does not follow the predictive formula but instead follows a similar model with a single Poisson ratio between the film and the substrate.
Journal of Materials Research, 2008
The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microte... more The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microtensile technique with applied strain rates on the order of 10−4 to 10−6 s−1. Film thickness ranged from 0.25 to 1.00 μm with corresponding grain sizes of 40 to 100 nm. The plastic properties were found to be particularly sensitive to strain rate, film thickness, and grain size, while the elastic property remained relatively unchanged. The thinner films exhibited significant strain rate sensitivity, while the thicker film exhibited only marginal changes. Hall–Petch boundary hardening was observed and dominated plastic flow at larger strain rates, while diffusion-controlled deformation mechanisms appeared to be activated with increasing influence as strain rate decreased. Analysis of dislocation-based and grain-boundary diffusion-related creep suggested that the films were likely experiencing power-law creep as the dominant deformation mechanism in this grain size regime at lower strain rates.
Journal of Materials Research, 2010
A new method to accurately and reliably extract the actual Young's modulus of a thin film on ... more A new method to accurately and reliably extract the actual Young's modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior a few nanometers into a film several hundred nanometers thick. The method was shown to work exceptionally well for all 25 different combinations of five films on five substrates that encompassed a wide range of compliant films on stiff substrates to stiff films on compliant substrates. A predictive formula was determined that enables the film modulus to be calculated as long as one knows the film thickness, substrate modulus, and bulk Poisson's ratio of the film and the substrate. The calculated values of the film modulus were verified with prior results that used the membrane deflection experiment and resonance-based methods. The greatest advantages of the method are that the standard Oliver ...
Journal of Electronic Packaging
The reliability of Sn-Ag-Cu (SAC)-based solder alloys has been extensively investigated after the... more The reliability of Sn-Ag-Cu (SAC)-based solder alloys has been extensively investigated after the prohibition of lead in the electronics industry owing to their toxicity. Low-temperature solder (LTS) alloys have recently received considerable attention because of their low cost and reduced defects in complex assemblies. The shear and fatigue properties of individual solder joints were tested using an Instron micromechanical testing system in this research. Two novel solder alloys (Sn-58Bi-0.5Sb-0.15Ni and Sn-42Bi) with low melting temperatures were examined and compared with Sn-3.5Ag and Sn-3.0Ag-0.8Cu-3.0Bi. The surface finish was electroless nickel-immersion gold (ENIG) during the test. Shear testing was conducted at three strain rates, and the shear strength of each solder alloy was measured. A constant strain rate was used for the cyclic fatigue experiments. The fatigue life of each alloy was determined for various stress amplitudes. The failure mechanism in shear and fatigue te...
Conference Proceedings of the Society for Experimental Mechanics Series, 2013
Many living organisms form biogenic minerals, or biominerals, which are composite materials conta... more Many living organisms form biogenic minerals, or biominerals, which are composite materials containing an organic matrix and nano- or micro-scale minerals assembled in a hierarchical architecture. These biogenic composites possess excellent mechanical properties in comparison to their abiogenic architectures (on the order of 3,000 times greater), which make them attractive for mechanically protective applications. One biogenic material that has garnered a lot of attention is Nacre, or “Mother of Pearl,” found in many Mollusk shells. The Nacre architecture has been well studied the past decade, however little work has focused on the fact that the Nacre composite is also itself a component of another composite architecture in the shells. In between thick layers of Nacre is a thin layer of an organic matrix that marks the seasonal growth patterns of the shells, analogous to tree rings. No work has focused on how these two layers interact to determine mechanical properties, which are likely as important as the tablet sliding itself. Determining this relationship would have a great impact on designing composite architectures that can improve the performance of mechanically protective armor.
Conference Proceedings of the Society for Experimental Mechanics Series, 2014
ABSTRACT
Experimental Mechanics, 2009
A new model of thin film indentation that accounted for an apparent discontinuity in elastic stra... more A new model of thin film indentation that accounted for an apparent discontinuity in elastic strain transfer at the film/substrate interface was developed. Finite element analysis suggested that numerical values of strain were not directly continuous across the interface; the values in the film were higher when a soft film was deposited on a hard substrate. The new model was constructed based on this discontinuity; whereby, separate weighting factors were applied to account for the influence of the substrate in strain developed in the film and vice-versa. By comparing the model to experimental data from thirteen different amorphous thin film materials on a silicon substrate, constants in each weighting factor were found to have physical significance in being numerically similar to the bulk scale Poisson's ratios of the materials involved. When employing these material properties in the new model it was found to provide an improved match to the experimental data over the existing Doerner and Nix and Gao models. Finally, the model was found to be capable of assessing the Young's modulus of thin films that do not exhibit a flat region as long as the bulk Poisson's ratio is known.
Experimental Mechanics, 2007
Microcantilever based sensors have been widely employed for measuring or detecting various hazard... more Microcantilever based sensors have been widely employed for measuring or detecting various hazardous chemical agents and biological agents. Although they have been successful in detecting agents of interest, researchers desire to improve their performance by enhancing their mass sensitivity towards developing "detect to warn" detection capabilities. Moreover, there has been little work aimed at tailoring beam mechanics as a means to enhance mass sensitivity. In this paper, a numerical study is performed to assess the influence of microcantilever geometry on mass sensitivity in order to improve these devices for better detection of hazardous biological agents in liquid environments. Modal analysis was performed on microcantilevers of different geometries and shapes using ANSYS software and compared to the basic rectangular shaped microcantilever structures employed by most researchers. These structures all possessed a 50 μm length, 0.5 μm thickness and 25 μm width where the cantilever is clamped to the substrate, and were analyzed for their basic resonance frequency as well as the frequency shift for the attachment of a 0.285 pg of mass attached on their surfaces. These numerical results indicated that two parameters dominate their behavior, (1) the effective mass of the cantilever at the free end and (2) the clamping width at the fixed end. The ideal geometry was a triangular shape, which minimized effective mass and maximized clamping width, resulting in an order of magnitude increase in mass sensitivity (1,775 Hz/pg) over rectangular shaped cantilevers (172 Hz/pg) of identical length and clamping width. The most practical geometry was triangular shaped cantilever with a square pad at the free end for capturing the agent of interest. This geometry resulted in a mass sensitivity of 628 Hz/pg or nearly a 4-fold increase in performance over their rectangular counterparts.
The residual stress and hardness of Inconel 625 fabricated using Laser Powder Bed Fusion (L-PBF) ... more The residual stress and hardness of Inconel 625 fabricated using Laser Powder Bed Fusion (L-PBF) were experimentally investigated. As-built Inconel 625 samples were subjected to three different heat-treatment temperatures of 700℃, 900℃, 1050℃ for one hour. Effects of these three-stress relieving heat treatment temperatures on the nature and value of residual stress were studied. Residual stress measurements were recorded using a portable X-ray system. The system calculated residual stress using the cos α method. The Full Width Half Maximum (FWHM) of diffraction peaks in all samples were measured. The results indicate that tensile residual stress was present on the surface of as-built L-PBF sample and compressive residual stress on the surface of heat-treated samples due to stress relief. Debye-Scherrer (D-S) ring positions were measured using the cos α method and compared with a reference wrought Inconel 625 ring position. Vickers microhardness and residual stress were found to be p...
Diffusion plays a paramount role in many scientific areas. In the scientific field, the term diff... more Diffusion plays a paramount role in many scientific areas. In the scientific field, the term diffusion coefficient, D, is generally used as the parameter for quantifying the diffusion phenomena. At present, diaphragm cell, chromatography or optical based methods are commonly employed to determine the D value of various solutions. However, these methods have major disadvantages; they use bulky equipment and require a lengthy experimental time. In the past, to overcome these disadvantages, many research groups have tried to reduce the size of the instrument, as well as decrease the performance time, by using microfluidic-based devices. This study will address the problem of achieving quick quantification of diffusion coefficients by using a novel micro system fluidic device. The major advantages of this device include minimum sample and device size, short experimental testing time, and user-friendly programming allowing for acceleration of determining a diffusion coefficient.
The mechanical behavior of freestanding gold membranes 0.5 µm thick with and with out passivation... more The mechanical behavior of freestanding gold membranes 0.5 µm thick with and with out passivation layers was studied with the Membrane Deflection Experiment (MDE). Membrane width was varied from 2.5 to 20 µm to investigate size effects. The presence of the passivation layer had the effect of reducing the membrane strength. Yield stress, as well as fracture strain and stress, were all found to be significantly lower for the passivated specimens. The residual stress state was found to be significantly larger with passivation, to the degree of generating pre-stressed cracks at micromachined notches. The effect of membrane width had the greatest effect on the residual stress state with smaller widths having larger residual stress.
MEMS and Nanotechnology, Volume 4, 2011
A new method to accurately and reliably extract the actual Young’s modulus of a thin film on a su... more A new method to accurately and reliably extract the actual Young’s modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior even a few nanometers into a film several hundred nanometers thick. The method was shown to
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Additive Manufacturing, 2021
In the red abalone’s shell, a special structure which has the unique morphology is named “mesolay... more In the red abalone’s shell, a special structure which has the unique morphology is named “mesolayer”. Its mechanical property is concerned in this research. The mesolayer is built with three sublayers: the columnar-like layer, the organic layer, and the prismatic layer. The three sublayers are tested with nanoindentation test individually and the results are analyzed. And, the nanoindentations on each layer are characterized by SEM.
It has been known for quite some time that materials and structures with small-scale dimensions d... more It has been known for quite some time that materials and structures with small-scale dimensions do not behave in the same manner as their bulk counterparts. This aspect was first observed in thin films where certain defect structures were found to have deleterious effects on the film’s structural integrity and reliability. This became a significant concern because thin films are routinely employed as components in microelectronics and microelectromechanical systems (MEMS). Their properties frequently allow essential device functions and therefore accurate identification of these properties is key to the development of new technologies. Unfortunately, most of our knowledge is based on bulk material behavior, which many times fails to describe material response in small-scale dimensions because of the dominance of surface and interface effects, finite number
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Oxide inclusions in stainless steel act as initiation sites for microvoids which result in signif... more Oxide inclusions in stainless steel act as initiation sites for microvoids which result in significant effects on mechanical properties. In the case of additive manufacturing (AM) 316L stainless steel, oxide inclusions can nucleate during laser melting and remain in the solidified microstructure. This work is aimed at assessing whether extraneous oxygen in process environment contributes to inclusion formation. The stainless-steel alloy 316L was employed and fabricated under series of different oxygen content environments. The characterization of oxide inclusions in AM processed materiel were conducted using scanning electron microscopy (SEM) and they are found enriched in oxygen getters such as Si and Mn. Inert gas fusion (IGF) was used to measure oxygen content before and after AM processing. Results indicated that extraneous oxygen from the process environment played a role in oxide inclusion formation. Furthermore, the average inclusion size was found to increase with increasing...
Smithells Metals Reference Book, 2004
Metallic materials that are outside the mainstream of conventional metals and alloys, with respec... more Metallic materials that are outside the mainstream of conventional metals and alloys, with respect to composition, structure and/or processing, are discussed in this chapter.
Conference Proceedings of the Society for Experimental Mechanics Series, 2013
A new method of accurately and reliably extract the actual Young's modulus of a thin film on a su... more A new method of accurately and reliably extract the actual Young's modulus of a thin film on a substrate has been developed. The method is referred to as the discontinuous elastic interface transfer model. The method has been shown to work exceptionally well with films and substrates encompassing a wide range of elastic moduli and Poisson ratios. The advantage of the method is that it does not require a continuous stiffness method and can use the standard Oliver and Pharr analysis and the use of a predictive formula for determining the modulus of the film as long as the film thickness, substrate modulus and bulk Poisson ratio of the film are known. However, when there is much pileup during the indentation process in a softer film, the experimental data does not follow the predictive formula but instead follows a similar model with a single Poisson ratio between the film and the substrate.
Journal of Materials Research, 2008
The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microte... more The strain rate dependence of freestanding, nanocrystalline gold films was evaluated by a microtensile technique with applied strain rates on the order of 10−4 to 10−6 s−1. Film thickness ranged from 0.25 to 1.00 μm with corresponding grain sizes of 40 to 100 nm. The plastic properties were found to be particularly sensitive to strain rate, film thickness, and grain size, while the elastic property remained relatively unchanged. The thinner films exhibited significant strain rate sensitivity, while the thicker film exhibited only marginal changes. Hall–Petch boundary hardening was observed and dominated plastic flow at larger strain rates, while diffusion-controlled deformation mechanisms appeared to be activated with increasing influence as strain rate decreased. Analysis of dislocation-based and grain-boundary diffusion-related creep suggested that the films were likely experiencing power-law creep as the dominant deformation mechanism in this grain size regime at lower strain rates.
Journal of Materials Research, 2010
A new method to accurately and reliably extract the actual Young's modulus of a thin film on ... more A new method to accurately and reliably extract the actual Young's modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior a few nanometers into a film several hundred nanometers thick. The method was shown to work exceptionally well for all 25 different combinations of five films on five substrates that encompassed a wide range of compliant films on stiff substrates to stiff films on compliant substrates. A predictive formula was determined that enables the film modulus to be calculated as long as one knows the film thickness, substrate modulus, and bulk Poisson's ratio of the film and the substrate. The calculated values of the film modulus were verified with prior results that used the membrane deflection experiment and resonance-based methods. The greatest advantages of the method are that the standard Oliver ...
Journal of Electronic Packaging
The reliability of Sn-Ag-Cu (SAC)-based solder alloys has been extensively investigated after the... more The reliability of Sn-Ag-Cu (SAC)-based solder alloys has been extensively investigated after the prohibition of lead in the electronics industry owing to their toxicity. Low-temperature solder (LTS) alloys have recently received considerable attention because of their low cost and reduced defects in complex assemblies. The shear and fatigue properties of individual solder joints were tested using an Instron micromechanical testing system in this research. Two novel solder alloys (Sn-58Bi-0.5Sb-0.15Ni and Sn-42Bi) with low melting temperatures were examined and compared with Sn-3.5Ag and Sn-3.0Ag-0.8Cu-3.0Bi. The surface finish was electroless nickel-immersion gold (ENIG) during the test. Shear testing was conducted at three strain rates, and the shear strength of each solder alloy was measured. A constant strain rate was used for the cyclic fatigue experiments. The fatigue life of each alloy was determined for various stress amplitudes. The failure mechanism in shear and fatigue te...
Conference Proceedings of the Society for Experimental Mechanics Series, 2013
Many living organisms form biogenic minerals, or biominerals, which are composite materials conta... more Many living organisms form biogenic minerals, or biominerals, which are composite materials containing an organic matrix and nano- or micro-scale minerals assembled in a hierarchical architecture. These biogenic composites possess excellent mechanical properties in comparison to their abiogenic architectures (on the order of 3,000 times greater), which make them attractive for mechanically protective applications. One biogenic material that has garnered a lot of attention is Nacre, or “Mother of Pearl,” found in many Mollusk shells. The Nacre architecture has been well studied the past decade, however little work has focused on the fact that the Nacre composite is also itself a component of another composite architecture in the shells. In between thick layers of Nacre is a thin layer of an organic matrix that marks the seasonal growth patterns of the shells, analogous to tree rings. No work has focused on how these two layers interact to determine mechanical properties, which are likely as important as the tablet sliding itself. Determining this relationship would have a great impact on designing composite architectures that can improve the performance of mechanically protective armor.
Conference Proceedings of the Society for Experimental Mechanics Series, 2014
ABSTRACT
Experimental Mechanics, 2009
A new model of thin film indentation that accounted for an apparent discontinuity in elastic stra... more A new model of thin film indentation that accounted for an apparent discontinuity in elastic strain transfer at the film/substrate interface was developed. Finite element analysis suggested that numerical values of strain were not directly continuous across the interface; the values in the film were higher when a soft film was deposited on a hard substrate. The new model was constructed based on this discontinuity; whereby, separate weighting factors were applied to account for the influence of the substrate in strain developed in the film and vice-versa. By comparing the model to experimental data from thirteen different amorphous thin film materials on a silicon substrate, constants in each weighting factor were found to have physical significance in being numerically similar to the bulk scale Poisson's ratios of the materials involved. When employing these material properties in the new model it was found to provide an improved match to the experimental data over the existing Doerner and Nix and Gao models. Finally, the model was found to be capable of assessing the Young's modulus of thin films that do not exhibit a flat region as long as the bulk Poisson's ratio is known.
Experimental Mechanics, 2007
Microcantilever based sensors have been widely employed for measuring or detecting various hazard... more Microcantilever based sensors have been widely employed for measuring or detecting various hazardous chemical agents and biological agents. Although they have been successful in detecting agents of interest, researchers desire to improve their performance by enhancing their mass sensitivity towards developing "detect to warn" detection capabilities. Moreover, there has been little work aimed at tailoring beam mechanics as a means to enhance mass sensitivity. In this paper, a numerical study is performed to assess the influence of microcantilever geometry on mass sensitivity in order to improve these devices for better detection of hazardous biological agents in liquid environments. Modal analysis was performed on microcantilevers of different geometries and shapes using ANSYS software and compared to the basic rectangular shaped microcantilever structures employed by most researchers. These structures all possessed a 50 μm length, 0.5 μm thickness and 25 μm width where the cantilever is clamped to the substrate, and were analyzed for their basic resonance frequency as well as the frequency shift for the attachment of a 0.285 pg of mass attached on their surfaces. These numerical results indicated that two parameters dominate their behavior, (1) the effective mass of the cantilever at the free end and (2) the clamping width at the fixed end. The ideal geometry was a triangular shape, which minimized effective mass and maximized clamping width, resulting in an order of magnitude increase in mass sensitivity (1,775 Hz/pg) over rectangular shaped cantilevers (172 Hz/pg) of identical length and clamping width. The most practical geometry was triangular shaped cantilever with a square pad at the free end for capturing the agent of interest. This geometry resulted in a mass sensitivity of 628 Hz/pg or nearly a 4-fold increase in performance over their rectangular counterparts.
The residual stress and hardness of Inconel 625 fabricated using Laser Powder Bed Fusion (L-PBF) ... more The residual stress and hardness of Inconel 625 fabricated using Laser Powder Bed Fusion (L-PBF) were experimentally investigated. As-built Inconel 625 samples were subjected to three different heat-treatment temperatures of 700℃, 900℃, 1050℃ for one hour. Effects of these three-stress relieving heat treatment temperatures on the nature and value of residual stress were studied. Residual stress measurements were recorded using a portable X-ray system. The system calculated residual stress using the cos α method. The Full Width Half Maximum (FWHM) of diffraction peaks in all samples were measured. The results indicate that tensile residual stress was present on the surface of as-built L-PBF sample and compressive residual stress on the surface of heat-treated samples due to stress relief. Debye-Scherrer (D-S) ring positions were measured using the cos α method and compared with a reference wrought Inconel 625 ring position. Vickers microhardness and residual stress were found to be p...
Diffusion plays a paramount role in many scientific areas. In the scientific field, the term diff... more Diffusion plays a paramount role in many scientific areas. In the scientific field, the term diffusion coefficient, D, is generally used as the parameter for quantifying the diffusion phenomena. At present, diaphragm cell, chromatography or optical based methods are commonly employed to determine the D value of various solutions. However, these methods have major disadvantages; they use bulky equipment and require a lengthy experimental time. In the past, to overcome these disadvantages, many research groups have tried to reduce the size of the instrument, as well as decrease the performance time, by using microfluidic-based devices. This study will address the problem of achieving quick quantification of diffusion coefficients by using a novel micro system fluidic device. The major advantages of this device include minimum sample and device size, short experimental testing time, and user-friendly programming allowing for acceleration of determining a diffusion coefficient.
The mechanical behavior of freestanding gold membranes 0.5 µm thick with and with out passivation... more The mechanical behavior of freestanding gold membranes 0.5 µm thick with and with out passivation layers was studied with the Membrane Deflection Experiment (MDE). Membrane width was varied from 2.5 to 20 µm to investigate size effects. The presence of the passivation layer had the effect of reducing the membrane strength. Yield stress, as well as fracture strain and stress, were all found to be significantly lower for the passivated specimens. The residual stress state was found to be significantly larger with passivation, to the degree of generating pre-stressed cracks at micromachined notches. The effect of membrane width had the greatest effect on the residual stress state with smaller widths having larger residual stress.
MEMS and Nanotechnology, Volume 4, 2011
A new method to accurately and reliably extract the actual Young’s modulus of a thin film on a su... more A new method to accurately and reliably extract the actual Young’s modulus of a thin film on a substrate by indentation was developed. The method involved modifying the discontinuous elastic interface transfer model to account for substrate effects that were found to influence behavior even a few nanometers into a film several hundred nanometers thick. The method was shown to
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Additive Manufacturing, 2021
In the red abalone’s shell, a special structure which has the unique morphology is named “mesolay... more In the red abalone’s shell, a special structure which has the unique morphology is named “mesolayer”. Its mechanical property is concerned in this research. The mesolayer is built with three sublayers: the columnar-like layer, the organic layer, and the prismatic layer. The three sublayers are tested with nanoindentation test individually and the results are analyzed. And, the nanoindentations on each layer are characterized by SEM.
It has been known for quite some time that materials and structures with small-scale dimensions d... more It has been known for quite some time that materials and structures with small-scale dimensions do not behave in the same manner as their bulk counterparts. This aspect was first observed in thin films where certain defect structures were found to have deleterious effects on the film’s structural integrity and reliability. This became a significant concern because thin films are routinely employed as components in microelectronics and microelectromechanical systems (MEMS). Their properties frequently allow essential device functions and therefore accurate identification of these properties is key to the development of new technologies. Unfortunately, most of our knowledge is based on bulk material behavior, which many times fails to describe material response in small-scale dimensions because of the dominance of surface and interface effects, finite number
Thermomechanics & Infrared Imaging, Inverse Problem Methodologies and Mechanics of Additive & Advanced Manufactured Materials, Volume 7, 2021
Oxide inclusions in stainless steel act as initiation sites for microvoids which result in signif... more Oxide inclusions in stainless steel act as initiation sites for microvoids which result in significant effects on mechanical properties. In the case of additive manufacturing (AM) 316L stainless steel, oxide inclusions can nucleate during laser melting and remain in the solidified microstructure. This work is aimed at assessing whether extraneous oxygen in process environment contributes to inclusion formation. The stainless-steel alloy 316L was employed and fabricated under series of different oxygen content environments. The characterization of oxide inclusions in AM processed materiel were conducted using scanning electron microscopy (SEM) and they are found enriched in oxygen getters such as Si and Mn. Inert gas fusion (IGF) was used to measure oxygen content before and after AM processing. Results indicated that extraneous oxygen from the process environment played a role in oxide inclusion formation. Furthermore, the average inclusion size was found to increase with increasing...