Vincenzo Tagliaferri | "Tor Vergata" University of Rome (original) (raw)

Papers by Vincenzo Tagliaferri

Research paper thumbnail of Transformation of the Structures and Compositions of the APS and LPPS Plasma Spayed Coatings Under Effect of Laser Radiation

CRC Press eBooks, Jan 19, 2023

Research paper thumbnail of L. Casamichele Process-Efficiency Prediction in High Power Diode Laser Forming

Research paper thumbnail of Improvement of the mechanical and thermal characteristics of open cell aluminum foams by the electrodeposition of Cu

Materials & Design, 2014

Research paper thumbnail of Machining Parameters and Cut Quality in Laser Cutting of Aramid Fibre Reinforced Plastics

Materials and Manufacturing Processes, 1990

ABSTRACT

Research paper thumbnail of Damage development in drilling glass fibre reinforced plastics

International Journal of Machine Tools and Manufacture, 1995

Research paper thumbnail of Physical and Technological Aspects Concerning the Heat Treatment of Glassy Metals by means of a Laser

High Temperature Materials and Processes, 1986

Research paper thumbnail of Effect of laser cutting on magnetic properties of grain oriented Fe–Si ribbons

Materials Science and Technology, 1992

Abstractypical Fe–Si sheets were cut using various techniques, reducing the material to ribbons h... more Abstractypical Fe–Si sheets were cut using various techniques, reducing the material to ribbons having their grains oriented parallel to the longitudinal axis. The magnetic and magnetoelastic properties in this direction reveal differences in the effects produced by conventional mechanical cutting in comparison with laser cutting. In particular, the latter technique results in both the highest saturation magnetisation level and the lowest values of coercive field, hysteresis loss, and saturation magnetostriction. It can be inferred from the results that laser cutting is effective in decreasing both induced stresses and defects on the cut edges.MST/1446

Research paper thumbnail of Surface finish of metal matrix composite under speed turning

Problems arising when machining metal matrix composites are the excessive abrasion of the cutting... more Problems arising when machining metal matrix composites are the excessive abrasion of the cutting tools by the reinforcing fibres and the poor quality of the surface finishing. The aim of the paper is the investigation of the last aspect in turning operations of metal matrix composites. Face turning trials under high speed conditions were performed on SiC whiskers/2009 Al and SiC particle /2009 Al employing uncoated carbide tools characterized by a positive side rake angle. The effects of the cutting parameters on the cut surface quality are described by statistical models. The morphology of machined surface, their sections and profiles were examined by SEM and using the suitable techniques

Research paper thumbnail of Neural networks approach for IR-heating and deformation of ABS in thermoforming

International Journal of Computer Applications in Technology, 2017

Research paper thumbnail of <title>Some Considerations On Laser Metal Cutting</title>

7th Intl Symp on Gas Flow and Chemical Lasers, 1989

The use of c.w. laser cutting of mild steel and aluminum alloys was already been investigated. As... more The use of c.w. laser cutting of mild steel and aluminum alloys was already been investigated. As others authors already pointed out, a converse proportion relation between thickness of material subjected to the cutting and speed of travel of the material itself takes place. In this work, refering to the previously obtained experimental data, we made some remarks on the above mentioned relation, in order to find a parameter which would be able to give useful instructions on the machinability of a fixed material by laser beam. In particular, we examined the effects on the above mentioned relation of three gases (Helium, Nitrogen, Oxygen) for different source power levels and on three kinds of materials (Aluminum alloy, Stainless steel, Mild steel). The law of correlation between thickness and speed was reviewed by some illustrative hypoteses. The obtained results seem to provide useful directions on the possibility to point out a technological parameter which could provide to laser systems consumers some information on optimization of processing conditions, by varying the maximum power of the source, the speed, the thickness, and the kind of material.

Research paper thumbnail of Hard transparent coatings on thermoplastic polycarbonate

Progress in Organic Coatings, 2016

Thermoplastic polycarbonates are widely used in several manufacturing domains because of their ex... more Thermoplastic polycarbonates are widely used in several manufacturing domains because of their extraordinary combination of transparency, toughness, ductility and chemical inertness at low and moderate temperature. They are, thus, ideal candidates to substitute float glasses, where lightweight and safety are of utmost relevance. In contrast, polycarbonates feature limited scratch and mar resistance, being characterized by very low surface hardness. This suggests the protection of polycarbonates with hard transparent coatings. However, poor interfacial adhesion between conventional coatings and polycarbonates, reduced cohesive strength of some hard coating materials and, in particular, their limited compliance when deposited on ductile substrates often reduce significantly their performance. In this respect, the present work analyzes the pros and cons of protecting thermoplastic polycarbonates with specialty coatings, emphasizing the real advantages of applying surface overlying layers and their drawbacks. Different formulations of the coatings were herein studied to optimize their interfacial adhesion with polycarbonates and cohesive strengths. Tribological (scratch, wear and mar) tests were, thus, performed to assess the performance of the coatings. After appropriate designing, specialty coatings might be useful to increase hardness and mar resistance of polycarbonates. Nevertheless, they are still largely ineffective to improve wear resistance of polycarbonates.

Research paper thumbnail of Partial anisotropy induced by low-field thermomagnetic treatment of noncrystalline ribbons

Il Nuovo Cimento D, 1989

SummaryThe initial development of the transverse anisotropy induced by magnetic annealing is inve... more SummaryThe initial development of the transverse anisotropy induced by magnetic annealing is investigated for magnetizing field values which are much smaller than the ones generally employed. Measurements of Young modulus and longitudinal magnetostriction not only show their relation with induced anistotropy, as predicted in a previous paper, but also enable us to calculate the easy magnetization direction. The results are in agreement with the distributed relaxation time theory.RiassuntoLa cinetica dell’anisotropia trasversale, indotta da trattamenti termomagnetici, è stata studiata per valori del campo magnetico notevolmente piú piccoli di quelli generalmente impiegati. Si dimostra la relazione del modulo di elasticità lineare e la magnetostrizione longitudinale con l’energia di anisotropia indotta, come già predetto in un precedente lavoro. In base alla coerenza dei risultati abbiamo potuto stimare la direzione di facile magnetizzazione indotta da trattamenti termomagnetici parziali. I risultati sono in accordo con l’ipotesi teorica di tempi di rilassamento distribuiti.РезюмеИсследуется начальное развитие поперечной анизотропии, индуцированной магнитным отжигом, в магнитных полях, напряженности которых очень малые по сравнению с обычно используемыми. Измерения модуля Юнга и продольной магнитострикции не только показывают связь с индуцированной анизотропией, но также позволяют вычислить направление легкого намагничивания. Полученные результаты согласуются с теорией.

Research paper thumbnail of Drilling Damage of GFRP and Residual Mechanical Behavior—Part I: Drilling Damage Generation

Journal of Composites Technology and Research, 2001

The drilling of composite laminates generates several kinds of damage that can be detrimental to ... more The drilling of composite laminates generates several kinds of damage that can be detrimental to the mechanical behavior around the hole. The present work is the first part of a study that investigates the effect of the drilling on the residual mechanical behavior of glass fiber reinforced plastic (GFRP) laminates when the hole is subjected to bearing load. In the first part, the influence of drilling parameters on the type and extension of the damage is analyzed. The damage is described at the macro level (delaminated area) and at the micro level (cracks, fiber-matrix debonding, etc.). The Design of Experiments and Analysis of Variance techniques are used in order to determine the statistical influence of the drilling parameters on the delamination area. Moreover, the effects of drilling with or without a support beneath the specimens are analyzed and discussed. Results indicate that the degree of peel-up delamination depends on the feed rate and on the helix angle of the twist drill. Push-down delamination is mainly affected by the feed rate, by the presence of support beneath the specimen, and by the twist drill temperature.

Research paper thumbnail of Tool life and hole quality in drilling aramid and fibrous composites

Research paper thumbnail of Scratch- and wear-resistant photoluminescent silicone epoxy coatings on floor tiles

Journal of Coatings Technology and Research, 2015

ABSTRACT Photoluminescent silicone epoxy resins were prepared by physical dispersion of SrAl2O4:E... more ABSTRACT Photoluminescent silicone epoxy resins were prepared by physical dispersion of SrAl2O4:Eu2+, Dy3+ pigments. The resin was deposited on ceramic tiles for flooring by automatic drawdown and left to harden at ambient conditions. Morphology of the coated tiles was measured by contact gage profilometry and field emission gun scanning electron microscopy. Mechanical response was investigated by pencil and cross-hatch scratch tests; depth-sensing indentation measurements were performed using Vickers and flat punch indenters. Tribological response of the coated tiles was measured by progressive and constant load scratch tests and dry sliding linearly reciprocating ball-on-flat tests, respectively. Intensity of photoluminescent radiations and the corresponding decay time were estimated by digital imaging. The photoluminescent coatings feature high hardness, scratch and wear endurance as well as good clarity. Being the resin designed for spontaneous drying and suitable for easy-to-automate and versatile deposition processes, it is the ideal candidate for the decoration of a large variety of substrates as well as for the repowering and/or retrofitting of previous installations.

Research paper thumbnail of Mechanical characterization of open cell aluminium foams reinforced by nickel electro-deposition

Materials & Design, 2015

Abstract The present study focused on the improvement of mechanical properties of open cell alumi... more Abstract The present study focused on the improvement of mechanical properties of open cell aluminium foams thanks to electro-deposition of nickel. In the first phase of the work, the parameters for the electro-deposition of nickel were optimized in order to increase the mechanical properties of these cellular materials. Different values of deposition currents and times were considered to vary the amount of nickel deposited. The performance improvement was evaluated by means of stress–strain curves. Strains were measured using a specifically developed optical extensometer with a resolution in strain of 14.1 micro-strains. A very low compression speed was set to provide a good temporal resolution given the type of camera used. Mechanical properties of aluminium foams coated by nickel or copper were compared according to the defined procedure to identify the effect of material and thickness of the coating. Stiffness was found not to be significantly affected by the electro-deposition of copper or nickel. On the contrary the maximum specific stress has been dramatically improved by the nickel coating.

Research paper thumbnail of An experimental study on the surface mechanisms formation during the laser milling of PMMA

Research paper thumbnail of Laser Welding Of Stainless Steel By Means Of "Flat-Top" Energy Distribution Beam

SPIE Proceedings, 1989

ABSTRACT

Research paper thumbnail of An Experimental Study of the Drilling of Aramid Composites

Journal of Energy Resources Technology, 1995

Major drilling characteristics of Aramid fiber-reinforced plastics are experimentally investigate... more Major drilling characteristics of Aramid fiber-reinforced plastics are experimentally investigated. The chip appears highly deformed and tends to smear on the tool. Forces and, mainly, torque are more influenced by the tool diameter than by the feed rate and cutting speed. On the contrary, the specific cutting energy strongly depends upon the feed rate due to size effects of the tool tip. The damage in the work, i.e., delamination at entry and exit side, can be controlled by taking into account the relationships between machining parameters and forces and torque. Generally, the tool fails by gross brittle failure at the periphery rather than by generalized land wear.

Research paper thumbnail of Heat Affected Zone Induced by Laser Forming

Research paper thumbnail of Transformation of the Structures and Compositions of the APS and LPPS Plasma Spayed Coatings Under Effect of Laser Radiation

CRC Press eBooks, Jan 19, 2023

Research paper thumbnail of L. Casamichele Process-Efficiency Prediction in High Power Diode Laser Forming

Research paper thumbnail of Improvement of the mechanical and thermal characteristics of open cell aluminum foams by the electrodeposition of Cu

Materials & Design, 2014

Research paper thumbnail of Machining Parameters and Cut Quality in Laser Cutting of Aramid Fibre Reinforced Plastics

Materials and Manufacturing Processes, 1990

ABSTRACT

Research paper thumbnail of Damage development in drilling glass fibre reinforced plastics

International Journal of Machine Tools and Manufacture, 1995

Research paper thumbnail of Physical and Technological Aspects Concerning the Heat Treatment of Glassy Metals by means of a Laser

High Temperature Materials and Processes, 1986

Research paper thumbnail of Effect of laser cutting on magnetic properties of grain oriented Fe–Si ribbons

Materials Science and Technology, 1992

Abstractypical Fe–Si sheets were cut using various techniques, reducing the material to ribbons h... more Abstractypical Fe–Si sheets were cut using various techniques, reducing the material to ribbons having their grains oriented parallel to the longitudinal axis. The magnetic and magnetoelastic properties in this direction reveal differences in the effects produced by conventional mechanical cutting in comparison with laser cutting. In particular, the latter technique results in both the highest saturation magnetisation level and the lowest values of coercive field, hysteresis loss, and saturation magnetostriction. It can be inferred from the results that laser cutting is effective in decreasing both induced stresses and defects on the cut edges.MST/1446

Research paper thumbnail of Surface finish of metal matrix composite under speed turning

Problems arising when machining metal matrix composites are the excessive abrasion of the cutting... more Problems arising when machining metal matrix composites are the excessive abrasion of the cutting tools by the reinforcing fibres and the poor quality of the surface finishing. The aim of the paper is the investigation of the last aspect in turning operations of metal matrix composites. Face turning trials under high speed conditions were performed on SiC whiskers/2009 Al and SiC particle /2009 Al employing uncoated carbide tools characterized by a positive side rake angle. The effects of the cutting parameters on the cut surface quality are described by statistical models. The morphology of machined surface, their sections and profiles were examined by SEM and using the suitable techniques

Research paper thumbnail of Neural networks approach for IR-heating and deformation of ABS in thermoforming

International Journal of Computer Applications in Technology, 2017

Research paper thumbnail of <title>Some Considerations On Laser Metal Cutting</title>

7th Intl Symp on Gas Flow and Chemical Lasers, 1989

The use of c.w. laser cutting of mild steel and aluminum alloys was already been investigated. As... more The use of c.w. laser cutting of mild steel and aluminum alloys was already been investigated. As others authors already pointed out, a converse proportion relation between thickness of material subjected to the cutting and speed of travel of the material itself takes place. In this work, refering to the previously obtained experimental data, we made some remarks on the above mentioned relation, in order to find a parameter which would be able to give useful instructions on the machinability of a fixed material by laser beam. In particular, we examined the effects on the above mentioned relation of three gases (Helium, Nitrogen, Oxygen) for different source power levels and on three kinds of materials (Aluminum alloy, Stainless steel, Mild steel). The law of correlation between thickness and speed was reviewed by some illustrative hypoteses. The obtained results seem to provide useful directions on the possibility to point out a technological parameter which could provide to laser systems consumers some information on optimization of processing conditions, by varying the maximum power of the source, the speed, the thickness, and the kind of material.

Research paper thumbnail of Hard transparent coatings on thermoplastic polycarbonate

Progress in Organic Coatings, 2016

Thermoplastic polycarbonates are widely used in several manufacturing domains because of their ex... more Thermoplastic polycarbonates are widely used in several manufacturing domains because of their extraordinary combination of transparency, toughness, ductility and chemical inertness at low and moderate temperature. They are, thus, ideal candidates to substitute float glasses, where lightweight and safety are of utmost relevance. In contrast, polycarbonates feature limited scratch and mar resistance, being characterized by very low surface hardness. This suggests the protection of polycarbonates with hard transparent coatings. However, poor interfacial adhesion between conventional coatings and polycarbonates, reduced cohesive strength of some hard coating materials and, in particular, their limited compliance when deposited on ductile substrates often reduce significantly their performance. In this respect, the present work analyzes the pros and cons of protecting thermoplastic polycarbonates with specialty coatings, emphasizing the real advantages of applying surface overlying layers and their drawbacks. Different formulations of the coatings were herein studied to optimize their interfacial adhesion with polycarbonates and cohesive strengths. Tribological (scratch, wear and mar) tests were, thus, performed to assess the performance of the coatings. After appropriate designing, specialty coatings might be useful to increase hardness and mar resistance of polycarbonates. Nevertheless, they are still largely ineffective to improve wear resistance of polycarbonates.

Research paper thumbnail of Partial anisotropy induced by low-field thermomagnetic treatment of noncrystalline ribbons

Il Nuovo Cimento D, 1989

SummaryThe initial development of the transverse anisotropy induced by magnetic annealing is inve... more SummaryThe initial development of the transverse anisotropy induced by magnetic annealing is investigated for magnetizing field values which are much smaller than the ones generally employed. Measurements of Young modulus and longitudinal magnetostriction not only show their relation with induced anistotropy, as predicted in a previous paper, but also enable us to calculate the easy magnetization direction. The results are in agreement with the distributed relaxation time theory.RiassuntoLa cinetica dell’anisotropia trasversale, indotta da trattamenti termomagnetici, è stata studiata per valori del campo magnetico notevolmente piú piccoli di quelli generalmente impiegati. Si dimostra la relazione del modulo di elasticità lineare e la magnetostrizione longitudinale con l’energia di anisotropia indotta, come già predetto in un precedente lavoro. In base alla coerenza dei risultati abbiamo potuto stimare la direzione di facile magnetizzazione indotta da trattamenti termomagnetici parziali. I risultati sono in accordo con l’ipotesi teorica di tempi di rilassamento distribuiti.РезюмеИсследуется начальное развитие поперечной анизотропии, индуцированной магнитным отжигом, в магнитных полях, напряженности которых очень малые по сравнению с обычно используемыми. Измерения модуля Юнга и продольной магнитострикции не только показывают связь с индуцированной анизотропией, но также позволяют вычислить направление легкого намагничивания. Полученные результаты согласуются с теорией.

Research paper thumbnail of Drilling Damage of GFRP and Residual Mechanical Behavior—Part I: Drilling Damage Generation

Journal of Composites Technology and Research, 2001

The drilling of composite laminates generates several kinds of damage that can be detrimental to ... more The drilling of composite laminates generates several kinds of damage that can be detrimental to the mechanical behavior around the hole. The present work is the first part of a study that investigates the effect of the drilling on the residual mechanical behavior of glass fiber reinforced plastic (GFRP) laminates when the hole is subjected to bearing load. In the first part, the influence of drilling parameters on the type and extension of the damage is analyzed. The damage is described at the macro level (delaminated area) and at the micro level (cracks, fiber-matrix debonding, etc.). The Design of Experiments and Analysis of Variance techniques are used in order to determine the statistical influence of the drilling parameters on the delamination area. Moreover, the effects of drilling with or without a support beneath the specimens are analyzed and discussed. Results indicate that the degree of peel-up delamination depends on the feed rate and on the helix angle of the twist drill. Push-down delamination is mainly affected by the feed rate, by the presence of support beneath the specimen, and by the twist drill temperature.

Research paper thumbnail of Tool life and hole quality in drilling aramid and fibrous composites

Research paper thumbnail of Scratch- and wear-resistant photoluminescent silicone epoxy coatings on floor tiles

Journal of Coatings Technology and Research, 2015

ABSTRACT Photoluminescent silicone epoxy resins were prepared by physical dispersion of SrAl2O4:E... more ABSTRACT Photoluminescent silicone epoxy resins were prepared by physical dispersion of SrAl2O4:Eu2+, Dy3+ pigments. The resin was deposited on ceramic tiles for flooring by automatic drawdown and left to harden at ambient conditions. Morphology of the coated tiles was measured by contact gage profilometry and field emission gun scanning electron microscopy. Mechanical response was investigated by pencil and cross-hatch scratch tests; depth-sensing indentation measurements were performed using Vickers and flat punch indenters. Tribological response of the coated tiles was measured by progressive and constant load scratch tests and dry sliding linearly reciprocating ball-on-flat tests, respectively. Intensity of photoluminescent radiations and the corresponding decay time were estimated by digital imaging. The photoluminescent coatings feature high hardness, scratch and wear endurance as well as good clarity. Being the resin designed for spontaneous drying and suitable for easy-to-automate and versatile deposition processes, it is the ideal candidate for the decoration of a large variety of substrates as well as for the repowering and/or retrofitting of previous installations.

Research paper thumbnail of Mechanical characterization of open cell aluminium foams reinforced by nickel electro-deposition

Materials & Design, 2015

Abstract The present study focused on the improvement of mechanical properties of open cell alumi... more Abstract The present study focused on the improvement of mechanical properties of open cell aluminium foams thanks to electro-deposition of nickel. In the first phase of the work, the parameters for the electro-deposition of nickel were optimized in order to increase the mechanical properties of these cellular materials. Different values of deposition currents and times were considered to vary the amount of nickel deposited. The performance improvement was evaluated by means of stress–strain curves. Strains were measured using a specifically developed optical extensometer with a resolution in strain of 14.1 micro-strains. A very low compression speed was set to provide a good temporal resolution given the type of camera used. Mechanical properties of aluminium foams coated by nickel or copper were compared according to the defined procedure to identify the effect of material and thickness of the coating. Stiffness was found not to be significantly affected by the electro-deposition of copper or nickel. On the contrary the maximum specific stress has been dramatically improved by the nickel coating.

Research paper thumbnail of An experimental study on the surface mechanisms formation during the laser milling of PMMA

Research paper thumbnail of Laser Welding Of Stainless Steel By Means Of "Flat-Top" Energy Distribution Beam

SPIE Proceedings, 1989

ABSTRACT

Research paper thumbnail of An Experimental Study of the Drilling of Aramid Composites

Journal of Energy Resources Technology, 1995

Major drilling characteristics of Aramid fiber-reinforced plastics are experimentally investigate... more Major drilling characteristics of Aramid fiber-reinforced plastics are experimentally investigated. The chip appears highly deformed and tends to smear on the tool. Forces and, mainly, torque are more influenced by the tool diameter than by the feed rate and cutting speed. On the contrary, the specific cutting energy strongly depends upon the feed rate due to size effects of the tool tip. The damage in the work, i.e., delamination at entry and exit side, can be controlled by taking into account the relationships between machining parameters and forces and torque. Generally, the tool fails by gross brittle failure at the periphery rather than by generalized land wear.

Research paper thumbnail of Heat Affected Zone Induced by Laser Forming