Edwin Martinez - Academia.edu (original) (raw)

Papers by Edwin Martinez

Research paper thumbnail of Next generation orthopaedic implants by additive manufacturing using electron beam melting

International journal of biomaterials, 2012

This paper presents some examples of knee and hip implant components containing porous structures... more This paper presents some examples of knee and hip implant components containing porous structures and fabricated in monolithic forms utilizing electron beam melting (EBM). In addition, utilizing stiffness or relative stiffness versus relative density design plots for open-cellular structures (mesh and foam components) of Ti-6Al-4V and Co-29Cr-6Mo alloy fabricated by EBM, it is demonstrated that stiffness-compatible implants can be fabricated for optimal stress shielding for bone regimes as well as bone cell ingrowth. Implications for the fabrication of patient-specific, monolithic, multifunctional orthopaedic implants using EBM are described along with microstructures and mechanical properties characteristic of both Ti-6Al-4V and Co-29Cr-6Mo alloy prototypes, including both solid and open-cellular prototypes manufactured by additive manufacturing (AM) using EBM.

Research paper thumbnail of Open-Cellular Co-Base and Ni-Base Superalloys Fabricated by Electron Beam Melting

Materials, 2011

Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam... more Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam samples of Co-29Cr-6Mo alloy fabricated by electron beam melting were characterized by optical metallography, and the dynamic stiffness (Young's modulus) was measured by resonant frequency analysis. The relative stiffness (E/E s ) versus relative density (ρ/ρ s ) plotted on a log-log basis resulted in a fitted straight line with a slope n ≅ 2, consistent with that for ideal open cellular materials.

Research paper thumbnail of Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies---Electron Beam Melting and Laser Beam Melting

Materials, 2011

Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grad... more Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into ...

Research paper thumbnail of Microstructures of Niobium Components Fabricated by Electron Beam Melting

Metallography, Microstructure, and Analysis, 2013

Research paper thumbnail of Microstructures and properties of solid and reticulated mesh components of pure iron fabricated by electron beam melting

Journal of Materials Research and Technology, 2013

Electron beam melting Dynamic stiffness Light and electron microscopy a b s t r a c t This resear... more Electron beam melting Dynamic stiffness Light and electron microscopy a b s t r a c t This research examines rapidly solidified, atomized pure iron powder and solid and reticulated mesh components fabricated by electron beam melting (EBM) from this powder precursor. Especially significant was the characterization of associated microstructures and corresponding mechanical properties. Atomized Fe powder was used to fabricate solid and reticulated mesh components by EBM. Powder and component microstructures and phase structures were examined by light (optical) metallography, scanning electron microscopy, X-ray diffractometry, and transmission electron microscopy. Corresponding Vickers microindentation hardness measurements were also made and compared to tensile data along with measurements of dynamic stiffness for mesh components having varying densities. The atomized Fe powder was observed to contain ␦-Fe which was retained in the solid, EBM-fabricated components where it was observed to be homogeneously distributed in equiaxed ␣-Fe grains as ␦-phase platelets measuring ∼0.5 m to 2 m in length and ∼40 nm thick; coincident with the ␣-Fe matrix {1 0 0} or {1 1 0} planes. A log-log plot of E/E s versus / s resulted in (E/E s ) = ( / s ) 2.8 . Novel, ␦-Fe phase platelets have been observed in ␣-Fe components fabricated by EMB. j m a t e r r e s t e c h n o l . 2 0 1 3;2(4):376-385

Research paper thumbnail of Microstructures for Two-Phase Gamma Titanium Aluminide Fabricated by Electron Beam Melting

Metallography, Microstructure, and Analysis, 2012

powder was used to fabricate solid, fully dense (3.85 g/cm 3 ) components by electron beam meltin... more powder was used to fabricate solid, fully dense (3.85 g/cm 3 ) components by electron beam melting (EBM). Foam components with densities from 0.33 to 0.46 g/cm 3 were also fabricated by EBM. Both the solid and the foam component microstructures were characterized by an equiaxed, duplex grain structure (15 lm diameter) containing lamellar a 2 (Ti 3 Al)/c (TiAl) plates *20 nm. Light optical metallography and transmission electron microscopy illustrated that these microstructures confirmed the (111) c /(001) a2 duplex orientation relationship. Solid components annealed at 1150°C at 5 h and 1380°C at 1 h exhibited a fine-grain (3 lm diameter) duplex structure and a large, equiaxed, fully lamellar grain structure (550 lm diameter), respectively. The lamellar structure consisted mostly of coherent {111} c (TiAl) twins with a width of *0.9 lm. These diverse annealed microstructures exhibited residual hardness values similar to the as-fabricated EBM components.

Research paper thumbnail of Fabricating Functional Ti-Alloy Biomedical Implants by Additive Manufacturing Using Electron Beam Melting

Journal of Biotechnology & Biomaterials, 2012

Research paper thumbnail of Fabrication of Metal and Alloy Components by Additive Manufacturing: Examples of 3D Materials Science

Journal of Materials Research and Technology, 2012

Research paper thumbnail of Contributions of Light Microscopy to Contemporary Materials Characterization: The New Directional Solidification

Metallography, Microstructure, and Analysis, 2012

In this article, we illustrate novel, columnar precipitate architectures in Co-base and Ni-base s... more In this article, we illustrate novel, columnar precipitate architectures in Co-base and Ni-base superalloys, and Cu components, directionally fabricated by electron beam melting; using light microscopy (LM). These microstructural architectures and related microstructural features are characteristic of a new directional solidification phenomenon created by selective melting of precursor powder layers, forming 3-dimensional (3D) products which result by additive manufacturing. Comprehensive, micron-scale observations rendered in 3D metallography are supplemented by transmission electron microscopy and scanning electron microscopy to provide a structural and microstructural overview. These observations illustrate the continuing importance of LM in contemporary materials characterization applied to advanced metals technologies.

Research paper thumbnail of Metallographic Characterization of Additive-Layer Manufactured Products by Electron Beam Melting of Ti-6Al-4V Powder

Practical Metallography, 2009

Résumé/Abstract Optical metallography and electron metallography (SEM and TEM) techniques are app... more Résumé/Abstract Optical metallography and electron metallography (SEM and TEM) techniques are applied to the characterization of additive-layer manufactured products and prototypes by electron beam melting (EBM) of Ti-6Al-4V atomized precursor powder. In ...

Research paper thumbnail of Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies—Electron Beam Melting and Laser Beam Melting

Materials, 2011

Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grad... more Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into ...

Research paper thumbnail of Open-Cellular Co-Base and Ni-Base Superalloys Fabricated by Electron Beam Melting

Materials, 2011

Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam... more Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam samples of Co-29Cr-6Mo alloy fabricated by electron beam melting were characterized by optical metallography, and the dynamic stiffness (Young's modulus) was measured by resonant frequency analysis. The relative stiffness (E/E s ) versus relative density (ρ/ρ s ) plotted on a log-log basis resulted in a fitted straight line with a slope n ≅ 2, consistent with that for ideal open cellular materials.

Research paper thumbnail of Metal Fabrication by Additive Manufacturing Using Laser and Electron Beam Melting Technologies

Journal of Materials Science & Technology, 2012

Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive ... more Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive manufacturing technologies which can allow for the fabrication of complex, multi-functional metal or alloy monoliths by CAD-directed, selective melting of precursor powder beds. By altering the beam parameters and scan strategies, new and unusual, even non-equilibrium microstructures can be produced; including controlled microstructural architectures which ideally extend the contemporary materials science and engineering paradigm relating structure-properties-processing-performance. In this study, comparative examples for SLM and EBM fabricated components from pre-alloyed, atomized precursor powders are presented. These include Cu, Ti-6Al-4V, alloy 625 (a Ni-base superalloy), a Co-base superalloy, and 17-4 PH stainless steel. These systems are characterized by optical metallography, scanning and transmission electron microscopy, and X-ray diffraction.

Research paper thumbnail of A review of equine dental disorders

Equine dentistry is a very important but until recently rather neglected area of equine practice,... more Equine dentistry is a very important but until recently rather neglected area of equine practice, with many horses suffering from undiagnosed, painful dental disorders. A thorough clinical examination using a full mouth speculum is a pre-requisite to performing any equine dental procedure. Common incisor disorders include: prolonged retention of deciduous incisors, supernumerary incisors and overjet -the latter usually accompanied by cheek teeth (CT) overgrowths. Overjet can be surgically corrected, but perhaps should not be in breeding animals. In younger horses, traumatically fractured incisors with pulpar exposure may survive by laying down tertiary dentine. Loss or maleruption of incisors can cause uneven occlusal wear that can affect mastication. Idiopathic fractures and apical infection of incisors are rare. The main disorder of canine teeth is the development of calculus of the lower canines, and occasionally, developmental displacements and traumatic fractures. The main indications for extraction of ''wolf teeth'' (Triadan 05s) are the presence of displaced or enlarged wolf teeth, or their presence in the mandible.

Research paper thumbnail of Next generation orthopaedic implants by additive manufacturing using electron beam melting

International journal of biomaterials, 2012

This paper presents some examples of knee and hip implant components containing porous structures... more This paper presents some examples of knee and hip implant components containing porous structures and fabricated in monolithic forms utilizing electron beam melting (EBM). In addition, utilizing stiffness or relative stiffness versus relative density design plots for open-cellular structures (mesh and foam components) of Ti-6Al-4V and Co-29Cr-6Mo alloy fabricated by EBM, it is demonstrated that stiffness-compatible implants can be fabricated for optimal stress shielding for bone regimes as well as bone cell ingrowth. Implications for the fabrication of patient-specific, monolithic, multifunctional orthopaedic implants using EBM are described along with microstructures and mechanical properties characteristic of both Ti-6Al-4V and Co-29Cr-6Mo alloy prototypes, including both solid and open-cellular prototypes manufactured by additive manufacturing (AM) using EBM.

Research paper thumbnail of Open-Cellular Co-Base and Ni-Base Superalloys Fabricated by Electron Beam Melting

Materials, 2011

Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam... more Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam samples of Co-29Cr-6Mo alloy fabricated by electron beam melting were characterized by optical metallography, and the dynamic stiffness (Young's modulus) was measured by resonant frequency analysis. The relative stiffness (E/E s ) versus relative density (ρ/ρ s ) plotted on a log-log basis resulted in a fitted straight line with a slope n ≅ 2, consistent with that for ideal open cellular materials.

Research paper thumbnail of Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies---Electron Beam Melting and Laser Beam Melting

Materials, 2011

Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grad... more Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into ...

Research paper thumbnail of Microstructures of Niobium Components Fabricated by Electron Beam Melting

Metallography, Microstructure, and Analysis, 2013

Research paper thumbnail of Microstructures and properties of solid and reticulated mesh components of pure iron fabricated by electron beam melting

Journal of Materials Research and Technology, 2013

Electron beam melting Dynamic stiffness Light and electron microscopy a b s t r a c t This resear... more Electron beam melting Dynamic stiffness Light and electron microscopy a b s t r a c t This research examines rapidly solidified, atomized pure iron powder and solid and reticulated mesh components fabricated by electron beam melting (EBM) from this powder precursor. Especially significant was the characterization of associated microstructures and corresponding mechanical properties. Atomized Fe powder was used to fabricate solid and reticulated mesh components by EBM. Powder and component microstructures and phase structures were examined by light (optical) metallography, scanning electron microscopy, X-ray diffractometry, and transmission electron microscopy. Corresponding Vickers microindentation hardness measurements were also made and compared to tensile data along with measurements of dynamic stiffness for mesh components having varying densities. The atomized Fe powder was observed to contain ␦-Fe which was retained in the solid, EBM-fabricated components where it was observed to be homogeneously distributed in equiaxed ␣-Fe grains as ␦-phase platelets measuring ∼0.5 m to 2 m in length and ∼40 nm thick; coincident with the ␣-Fe matrix {1 0 0} or {1 1 0} planes. A log-log plot of E/E s versus / s resulted in (E/E s ) = ( / s ) 2.8 . Novel, ␦-Fe phase platelets have been observed in ␣-Fe components fabricated by EMB. j m a t e r r e s t e c h n o l . 2 0 1 3;2(4):376-385

Research paper thumbnail of Microstructures for Two-Phase Gamma Titanium Aluminide Fabricated by Electron Beam Melting

Metallography, Microstructure, and Analysis, 2012

powder was used to fabricate solid, fully dense (3.85 g/cm 3 ) components by electron beam meltin... more powder was used to fabricate solid, fully dense (3.85 g/cm 3 ) components by electron beam melting (EBM). Foam components with densities from 0.33 to 0.46 g/cm 3 were also fabricated by EBM. Both the solid and the foam component microstructures were characterized by an equiaxed, duplex grain structure (15 lm diameter) containing lamellar a 2 (Ti 3 Al)/c (TiAl) plates *20 nm. Light optical metallography and transmission electron microscopy illustrated that these microstructures confirmed the (111) c /(001) a2 duplex orientation relationship. Solid components annealed at 1150°C at 5 h and 1380°C at 1 h exhibited a fine-grain (3 lm diameter) duplex structure and a large, equiaxed, fully lamellar grain structure (550 lm diameter), respectively. The lamellar structure consisted mostly of coherent {111} c (TiAl) twins with a width of *0.9 lm. These diverse annealed microstructures exhibited residual hardness values similar to the as-fabricated EBM components.

Research paper thumbnail of Fabricating Functional Ti-Alloy Biomedical Implants by Additive Manufacturing Using Electron Beam Melting

Journal of Biotechnology & Biomaterials, 2012

Research paper thumbnail of Fabrication of Metal and Alloy Components by Additive Manufacturing: Examples of 3D Materials Science

Journal of Materials Research and Technology, 2012

Research paper thumbnail of Contributions of Light Microscopy to Contemporary Materials Characterization: The New Directional Solidification

Metallography, Microstructure, and Analysis, 2012

In this article, we illustrate novel, columnar precipitate architectures in Co-base and Ni-base s... more In this article, we illustrate novel, columnar precipitate architectures in Co-base and Ni-base superalloys, and Cu components, directionally fabricated by electron beam melting; using light microscopy (LM). These microstructural architectures and related microstructural features are characteristic of a new directional solidification phenomenon created by selective melting of precursor powder layers, forming 3-dimensional (3D) products which result by additive manufacturing. Comprehensive, micron-scale observations rendered in 3D metallography are supplemented by transmission electron microscopy and scanning electron microscopy to provide a structural and microstructural overview. These observations illustrate the continuing importance of LM in contemporary materials characterization applied to advanced metals technologies.

Research paper thumbnail of Metallographic Characterization of Additive-Layer Manufactured Products by Electron Beam Melting of Ti-6Al-4V Powder

Practical Metallography, 2009

Résumé/Abstract Optical metallography and electron metallography (SEM and TEM) techniques are app... more Résumé/Abstract Optical metallography and electron metallography (SEM and TEM) techniques are applied to the characterization of additive-layer manufactured products and prototypes by electron beam melting (EBM) of Ti-6Al-4V atomized precursor powder. In ...

Research paper thumbnail of Evaluation of Titanium Alloys Fabricated Using Rapid Prototyping Technologies—Electron Beam Melting and Laser Beam Melting

Materials, 2011

Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grad... more Abstract: This study characterized properties of Ti-6Al-4V ELI (extra low interstitial, ASTM grade 23) specimens fabricated by a laser beam melting (LBM) and an electron beam melting (EBM) system for dental applications. Titanium alloy specimens were made into ...

Research paper thumbnail of Open-Cellular Co-Base and Ni-Base Superalloys Fabricated by Electron Beam Melting

Materials, 2011

Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam... more Reticulated mesh samples of Co-29Cr-6Mo alloy and Ni-21Cr-9Mo-4Nb alloy (625) and stochastic foam samples of Co-29Cr-6Mo alloy fabricated by electron beam melting were characterized by optical metallography, and the dynamic stiffness (Young's modulus) was measured by resonant frequency analysis. The relative stiffness (E/E s ) versus relative density (ρ/ρ s ) plotted on a log-log basis resulted in a fitted straight line with a slope n ≅ 2, consistent with that for ideal open cellular materials.

Research paper thumbnail of Metal Fabrication by Additive Manufacturing Using Laser and Electron Beam Melting Technologies

Journal of Materials Science & Technology, 2012

Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive ... more Selective laser melting (SLM) and electron beam melting (EBM) are relatively new rapid, additive manufacturing technologies which can allow for the fabrication of complex, multi-functional metal or alloy monoliths by CAD-directed, selective melting of precursor powder beds. By altering the beam parameters and scan strategies, new and unusual, even non-equilibrium microstructures can be produced; including controlled microstructural architectures which ideally extend the contemporary materials science and engineering paradigm relating structure-properties-processing-performance. In this study, comparative examples for SLM and EBM fabricated components from pre-alloyed, atomized precursor powders are presented. These include Cu, Ti-6Al-4V, alloy 625 (a Ni-base superalloy), a Co-base superalloy, and 17-4 PH stainless steel. These systems are characterized by optical metallography, scanning and transmission electron microscopy, and X-ray diffraction.

Research paper thumbnail of A review of equine dental disorders

Equine dentistry is a very important but until recently rather neglected area of equine practice,... more Equine dentistry is a very important but until recently rather neglected area of equine practice, with many horses suffering from undiagnosed, painful dental disorders. A thorough clinical examination using a full mouth speculum is a pre-requisite to performing any equine dental procedure. Common incisor disorders include: prolonged retention of deciduous incisors, supernumerary incisors and overjet -the latter usually accompanied by cheek teeth (CT) overgrowths. Overjet can be surgically corrected, but perhaps should not be in breeding animals. In younger horses, traumatically fractured incisors with pulpar exposure may survive by laying down tertiary dentine. Loss or maleruption of incisors can cause uneven occlusal wear that can affect mastication. Idiopathic fractures and apical infection of incisors are rare. The main disorder of canine teeth is the development of calculus of the lower canines, and occasionally, developmental displacements and traumatic fractures. The main indications for extraction of ''wolf teeth'' (Triadan 05s) are the presence of displaced or enlarged wolf teeth, or their presence in the mandible.