R. Montanari | Università di Roma Tor Vergata (original) (raw)

Papers by R. Montanari

Renewable Energy and Power Quality Journal, 2012

Since some years, European companies are interested in the issue of energy saving. In such contex... more Since some years, European companies are interested in the issue of energy saving. In such context, a classification of industrial machines from the energetic point of view is becoming more and more important; currently, in the industrial context, no similar classifications exist. The aim of this work is to formulate a standard method to evaluate the energy performance of an industrial machine, such as a shrinkwrap-packer. To this purpose, we studied a shrinkwrap-packer produced by OCME S.r.l, a mechanical machinery company located in Parma (Italy). Specifically, the shrinkwrap-packer was analyzed in terms of energy dissipations and other aspects related to the energy source utilized to power the oven. As a result, we propose a general procedure that allows to compare different solutions from different perspectives related to energy efficiency. More precisely, we include three key performance indicators (KPIs) of energy efficiency, to build a comprehensive evaluation model. The first KPI concerns the energy efficiency class of the oven, the second KPI takes into account the impact of the oven on the work environment and the third one is an index of degradation of the energy resource utilized. A Global Index of Energy Efficiency (GI) is finally computed as the area of a triangle represented on a radar diagram on three axes, one for each KPI.

Materials Science and Engineering: A, 1999

X-ray diffraction (XRD) measurements were employed to study the martensite reversion in an Fe-21%... more X-ray diffraction (XRD) measurements were employed to study the martensite reversion in an Fe-21%Mn-0.1%C (wt.) alloy with an initial fully martensitic structure (o+2% a) induced by cold rolling. The samples were mounted in a high temperature XRD camera and were subjected to heat treatments of 1.2× 10 3 s at increasing temperatures (step 50 K) from 373 to 773 K. So, after each heating step, it was possible to collect high precision XRD line profiles from the same zone. Traces of g phase appear after the heating at 573 K, and after 723 K the transformation is completed. The newly formed g phase has a high density of stacking faults and several relief steps appear on the surface of previously mirror-like polished samples. The surface morphology was examined by optical, scanning electron and scanning tunnelling microscopy. The results indicate that the og transformation is a martensitic transformation taking place by faulting mechanism.

Journal of Nuclear Materials, 2007

Flat-top cylinder indenter for mechanical characterization (FIMEC) is an indentation technique em... more Flat-top cylinder indenter for mechanical characterization (FIMEC) is an indentation technique employing cylindrical punches with diameters ranging from 0.5 to 2 mm. The test gives pressure-penetration curves from which the yield stress can be determined. The FIMEC apparatus was developed to test materials in the temperature range from À180 to +200°C. Recently, the heating system of FIMEC apparatus has been modified to operate up to 500°C. So, in addition to providing yield stress over a more extended temperature range, it is possible to perform stress-relaxation tests at temperatures of great interest for several nuclear fusion reactor (NFR) alloys. Data on MANET-II, F82H mod., Eurofer-97, EM-10, AISI 316 L, Ti6Al4V and CuCrZr are presented and compared with those obtained by mechanical tests with standard methods.

Metallurgia Italiana, 2006

... riguardanti l'estrusione di allumi-nio e le saldature nell'acciaio ... more ... riguardanti l'estrusione di allumi-nio e le saldature nell'acciaio Eurofer-97, materiale previsto per applicazioni strutturali nei futuri reattori a fusione ... attivazione candidati per la realizzazione del TBM (Tri-tium Blanket Moduli) di ITER o di DEMO, futuri reattori a fusione ...

Surface and Interface Analysis, 2010

The composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has... more The composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has been investigated through a new fabrication process, roll diffusion bonding (RDB), developed at the CSM laboratories. Microchemical characteristics of the interface between carbon (coating of SiC fibres) and metal (Ti6Al4V) have been investigated by means of XPS, multipoint AES and photoemission spectromicroscopy (Electron Spectroscopy for Chemical Analysis (ESCA) microscopy beamline at the ELETTRA synchrotron light source). The results obtained revealed that the composition of the fibre–metal interface is similar to that of the composites produced by conventional method of hot isostatic pressing (HIP).In the matrix, near to the fibres, the anomalous shape of Al 2p signal indicated the presence of CAl atom pairs which are responsible for the anelastic characteristics of the composite. Copyright © 2010 John Wiley & Sons, Ltd.

Fusion Technology 1992, 1993

The effects of tempering at 700°C of MANET steel for subsequent times have been examined on tough... more The effects of tempering at 700°C of MANET steel for subsequent times have been examined on toughness, ductile to brittle transition, hardness, X-ray diffraction line widths, SEM metallography and micro-analytical maps.Results are interpreted with reference to characteristics of Cr atom distribution in solution.

Materials Science Forum, 2009

The microstructure of Ti6Al4V-SiCf composite, in as-fabricated condition and after long-term heat... more The microstructure of Ti6Al4V-SiCf composite, in as-fabricated condition and after long-term heat treatments (up to 1,000 hours) in the temperature range 400 - 600 °C, has been investigated by means of high-temperature X-ray diffraction (HT-XRD), energy dispersion spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Particular attention was paid to the strains, arising during heating, and to the micro-chemical evolution of fibre-matrix interface. Micro-chemical examinations evidenced that a thin TiC layer has formed between the fibre carbon coating and the matrix during the fabrication process. TiC slows down further diffusion of carbon towards the matrix and guarantees the interface stability also for the most severe treatments examined here.

NEUMANN:STEELS O-BK, 2000

Materials Science and Engineering: A, 2006

Optical, scanning electron, and scanning tunneling microscopy, as well as X-ray diffraction, were... more Optical, scanning electron, and scanning tunneling microscopy, as well as X-ray diffraction, were employed to detect microstructural modifications caused in AISI 304Cu steel disks by explosions of small charges placed at close ranges. Explosions induced limited or no gross macro-deformation. NSP (plastic) explosive spherical charges of 54.5 and 109 g TNT equivalent mass and explosive-to-target distances in the range from 6.5 to 81.5 cm were used to achieve peak pressures in the 160-0.5 MPa range. Two alloy grain sizes (60 and 32 m) were tested. Surface optical and scanning electron microscopy revealed partial surface melting, zones with indications of recrystallization, and intense mechanical twinning, which was detected also by X-ray diffraction. In the interior of the samples, twins were exclusively found. They can be seen up to some distance from the explosion-impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For metal object mapping after explosions, an important source of information in forensic science, the maximum charge-to-target distance at which the phenomena disappear has been singled out for each charge and alloy grain size and related to the critical resolved shear stress for twinning.

Journal of Nuclear Materials, 2002

Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on ... more Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project – Structural Materials Program.

Journal of Nuclear Materials, 2004

ABSTRACT

Le Journal de Physique IV, 1996

Snoek type Q-' peaks observed in Fe-Cr-C alloys are related to jumps between equivalent octahedra... more Snoek type Q-' peaks observed in Fe-Cr-C alloys are related to jumps between equivalent octahedra or tetrahedra with n Cr atoms at the corners, with n up to 6 or 4. The effects of high T and cooling treatments are considered on the characteristics of the C-Cr, associates and in consequence of martensite.The results are interpreted in terms of C-Cr, associates acting as embryos for the nucleation of martensite with stability depending on tetrahedrality or octahedrality of the associates.

Un modello di Reti Neurali Artificiali (RNA) quantitativo non lineare e stato implementato per pr... more Un modello di Reti Neurali Artificiali (RNA) quantitativo non lineare e stato implementato per prevedere il comportamento superplastico della lega PbSn60. Il motivo dell’impiego delle reti neurali come sistema di previsione risiede nella loro capacita di ricostruire la relazione ingresso/uscita di un qualunque processo in mancanza di un modello funzionale. La caratteristica principale delle reti neurali e proprio quella di potersi adattare a condizioni di applicazioni differenti, sfruttando la propria capacita di generalizzazione e utilizzando un insieme di dati sperimentali di riferimento (training set) come esperienza passata sulla quale basarsi per la risoluzione del problema in questione. In questo lavoro i dati per l’addestramento della rete derivano dalla caratterizzazione meccanica e microstrutturale della lega PbSn60. In particolare la caratterizzazione meccanica e stata effettuata mediante prove di trazione a velocita della traversa costante. Sono stati rilevati in scala logaritmica i valori della tensione corrispondenti alla stessa deformazione ma valutati a differenti velocita. Il valore dell’indice di sensibilita alla velocita di deformazione (m) e stato ottenuto analizzando la pendenza della retta interpolante l’andamento di log  vs log . La rete si e rivelata un valido strumento per la previsione del comportamento superplastico, ottimizzando tempi e costi della sperimentazione.

L’obiettivo principale di questo lavoro e stato lo studio della variazione di densita relativa e ... more L’obiettivo principale di questo lavoro e stato lo studio della variazione di densita relativa e delle caratteristiche morfologiche (dimensione media, distribuzione delle dimensioni e forma) delle schiume in funzione della composizione del precursore. In particolare si e visto che la crescita della schiuma dipende dalla quantita di idruro di titanio, tuttavia superata una certa frazione di TiH2 (0.4% in peso) la densita rimane sostanzialmente costante. Per poter stabilire le condizioni ottimali di processo su una griglia piu fitta di composizioni, limitando il numero di esperimenti da eseguire, sono state implementate due reti neurali artificiali. I risultati mostrano un buon accordo tra i dati sperimentali e i valori calcolati e la differenza e confrontabile con la dispersione dei dati sperimentali. Pertanto, le reti neurali implementate si dimostrano essere un ottimo strumento per l’ottimizzazione dei parametri di processo delle schiume metalliche. Si e poi voluto in particolare analizzare quali fossero le composizioni e le caratteristiche morfologiche piu idonee per avere un migliore assorbimento di energia. Le prove meccaniche statiche e dinamiche indicano chiaramente come il fattore piu importante affinche le schiume possano assorbire energia in un processo di deformazione plastica e la densita. Tanto piu bassa e la densita tanto migliore e il comportamento della schiuma. Per questa ragione schiume di alluminio da applicarsi con la funzione di assorbire urti o smorzare vibrazioni debbono essere a bassa densita e quindi prodotte con una quantita di idruro di titanio uguale o maggiore a 0.4%. Al fine di ottimizzare le prestazioni si dovranno poi scegliere quelle la cui composizione fornisce bolle di dimensione piccola, omogenea e rotonda.

Composites Part B: Engineering, 2005

Fatigue life and endurance limit of Metal Matrix Composites (MMCs), reinforced with ceramic parti... more Fatigue life and endurance limit of Metal Matrix Composites (MMCs), reinforced with ceramic particles, have been remarkably increased by means of thin Ti coatings sputtered at room temperature. The method has been successfully tested for composites of Al alloys (6061, A359, 2618) with different reinforcement particles (Al2O3, SiC). Some alloys were prepared by molten metal process, others by powder metallurgy.

Journal of Nuclear Materials, 2002

Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on ... more Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project – Structural Materials Program.

Renewable Energy and Power Quality Journal, 2012

Since some years, European companies are interested in the issue of energy saving. In such contex... more Since some years, European companies are interested in the issue of energy saving. In such context, a classification of industrial machines from the energetic point of view is becoming more and more important; currently, in the industrial context, no similar classifications exist. The aim of this work is to formulate a standard method to evaluate the energy performance of an industrial machine, such as a shrinkwrap-packer. To this purpose, we studied a shrinkwrap-packer produced by OCME S.r.l, a mechanical machinery company located in Parma (Italy). Specifically, the shrinkwrap-packer was analyzed in terms of energy dissipations and other aspects related to the energy source utilized to power the oven. As a result, we propose a general procedure that allows to compare different solutions from different perspectives related to energy efficiency. More precisely, we include three key performance indicators (KPIs) of energy efficiency, to build a comprehensive evaluation model. The first KPI concerns the energy efficiency class of the oven, the second KPI takes into account the impact of the oven on the work environment and the third one is an index of degradation of the energy resource utilized. A Global Index of Energy Efficiency (GI) is finally computed as the area of a triangle represented on a radar diagram on three axes, one for each KPI.

Materials Science and Engineering: A, 1999

X-ray diffraction (XRD) measurements were employed to study the martensite reversion in an Fe-21%... more X-ray diffraction (XRD) measurements were employed to study the martensite reversion in an Fe-21%Mn-0.1%C (wt.) alloy with an initial fully martensitic structure (o+2% a) induced by cold rolling. The samples were mounted in a high temperature XRD camera and were subjected to heat treatments of 1.2× 10 3 s at increasing temperatures (step 50 K) from 373 to 773 K. So, after each heating step, it was possible to collect high precision XRD line profiles from the same zone. Traces of g phase appear after the heating at 573 K, and after 723 K the transformation is completed. The newly formed g phase has a high density of stacking faults and several relief steps appear on the surface of previously mirror-like polished samples. The surface morphology was examined by optical, scanning electron and scanning tunnelling microscopy. The results indicate that the og transformation is a martensitic transformation taking place by faulting mechanism.

Journal of Nuclear Materials, 2007

Flat-top cylinder indenter for mechanical characterization (FIMEC) is an indentation technique em... more Flat-top cylinder indenter for mechanical characterization (FIMEC) is an indentation technique employing cylindrical punches with diameters ranging from 0.5 to 2 mm. The test gives pressure-penetration curves from which the yield stress can be determined. The FIMEC apparatus was developed to test materials in the temperature range from À180 to +200°C. Recently, the heating system of FIMEC apparatus has been modified to operate up to 500°C. So, in addition to providing yield stress over a more extended temperature range, it is possible to perform stress-relaxation tests at temperatures of great interest for several nuclear fusion reactor (NFR) alloys. Data on MANET-II, F82H mod., Eurofer-97, EM-10, AISI 316 L, Ti6Al4V and CuCrZr are presented and compared with those obtained by mechanical tests with standard methods.

Metallurgia Italiana, 2006

... riguardanti l'estrusione di allumi-nio e le saldature nell'acciaio ... more ... riguardanti l'estrusione di allumi-nio e le saldature nell'acciaio Eurofer-97, materiale previsto per applicazioni strutturali nei futuri reattori a fusione ... attivazione candidati per la realizzazione del TBM (Tri-tium Blanket Moduli) di ITER o di DEMO, futuri reattori a fusione ...

Surface and Interface Analysis, 2010

The composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has... more The composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has been investigated through a new fabrication process, roll diffusion bonding (RDB), developed at the CSM laboratories. Microchemical characteristics of the interface between carbon (coating of SiC fibres) and metal (Ti6Al4V) have been investigated by means of XPS, multipoint AES and photoemission spectromicroscopy (Electron Spectroscopy for Chemical Analysis (ESCA) microscopy beamline at the ELETTRA synchrotron light source). The results obtained revealed that the composition of the fibre–metal interface is similar to that of the composites produced by conventional method of hot isostatic pressing (HIP).In the matrix, near to the fibres, the anomalous shape of Al 2p signal indicated the presence of CAl atom pairs which are responsible for the anelastic characteristics of the composite. Copyright © 2010 John Wiley & Sons, Ltd.

Fusion Technology 1992, 1993

The effects of tempering at 700°C of MANET steel for subsequent times have been examined on tough... more The effects of tempering at 700°C of MANET steel for subsequent times have been examined on toughness, ductile to brittle transition, hardness, X-ray diffraction line widths, SEM metallography and micro-analytical maps.Results are interpreted with reference to characteristics of Cr atom distribution in solution.

Materials Science Forum, 2009

The microstructure of Ti6Al4V-SiCf composite, in as-fabricated condition and after long-term heat... more The microstructure of Ti6Al4V-SiCf composite, in as-fabricated condition and after long-term heat treatments (up to 1,000 hours) in the temperature range 400 - 600 °C, has been investigated by means of high-temperature X-ray diffraction (HT-XRD), energy dispersion spectrometry (EDS), X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Particular attention was paid to the strains, arising during heating, and to the micro-chemical evolution of fibre-matrix interface. Micro-chemical examinations evidenced that a thin TiC layer has formed between the fibre carbon coating and the matrix during the fabrication process. TiC slows down further diffusion of carbon towards the matrix and guarantees the interface stability also for the most severe treatments examined here.

NEUMANN:STEELS O-BK, 2000

Materials Science and Engineering: A, 2006

Optical, scanning electron, and scanning tunneling microscopy, as well as X-ray diffraction, were... more Optical, scanning electron, and scanning tunneling microscopy, as well as X-ray diffraction, were employed to detect microstructural modifications caused in AISI 304Cu steel disks by explosions of small charges placed at close ranges. Explosions induced limited or no gross macro-deformation. NSP (plastic) explosive spherical charges of 54.5 and 109 g TNT equivalent mass and explosive-to-target distances in the range from 6.5 to 81.5 cm were used to achieve peak pressures in the 160-0.5 MPa range. Two alloy grain sizes (60 and 32 m) were tested. Surface optical and scanning electron microscopy revealed partial surface melting, zones with indications of recrystallization, and intense mechanical twinning, which was detected also by X-ray diffraction. In the interior of the samples, twins were exclusively found. They can be seen up to some distance from the explosion-impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For metal object mapping after explosions, an important source of information in forensic science, the maximum charge-to-target distance at which the phenomena disappear has been singled out for each charge and alloy grain size and related to the critical resolved shear stress for twinning.

Journal of Nuclear Materials, 2002

Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on ... more Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project – Structural Materials Program.

Journal of Nuclear Materials, 2004

ABSTRACT

Le Journal de Physique IV, 1996

Snoek type Q-' peaks observed in Fe-Cr-C alloys are related to jumps between equivalent octahedra... more Snoek type Q-' peaks observed in Fe-Cr-C alloys are related to jumps between equivalent octahedra or tetrahedra with n Cr atoms at the corners, with n up to 6 or 4. The effects of high T and cooling treatments are considered on the characteristics of the C-Cr, associates and in consequence of martensite.The results are interpreted in terms of C-Cr, associates acting as embryos for the nucleation of martensite with stability depending on tetrahedrality or octahedrality of the associates.

Un modello di Reti Neurali Artificiali (RNA) quantitativo non lineare e stato implementato per pr... more Un modello di Reti Neurali Artificiali (RNA) quantitativo non lineare e stato implementato per prevedere il comportamento superplastico della lega PbSn60. Il motivo dell’impiego delle reti neurali come sistema di previsione risiede nella loro capacita di ricostruire la relazione ingresso/uscita di un qualunque processo in mancanza di un modello funzionale. La caratteristica principale delle reti neurali e proprio quella di potersi adattare a condizioni di applicazioni differenti, sfruttando la propria capacita di generalizzazione e utilizzando un insieme di dati sperimentali di riferimento (training set) come esperienza passata sulla quale basarsi per la risoluzione del problema in questione. In questo lavoro i dati per l’addestramento della rete derivano dalla caratterizzazione meccanica e microstrutturale della lega PbSn60. In particolare la caratterizzazione meccanica e stata effettuata mediante prove di trazione a velocita della traversa costante. Sono stati rilevati in scala logaritmica i valori della tensione corrispondenti alla stessa deformazione ma valutati a differenti velocita. Il valore dell’indice di sensibilita alla velocita di deformazione (m) e stato ottenuto analizzando la pendenza della retta interpolante l’andamento di log  vs log . La rete si e rivelata un valido strumento per la previsione del comportamento superplastico, ottimizzando tempi e costi della sperimentazione.

L’obiettivo principale di questo lavoro e stato lo studio della variazione di densita relativa e ... more L’obiettivo principale di questo lavoro e stato lo studio della variazione di densita relativa e delle caratteristiche morfologiche (dimensione media, distribuzione delle dimensioni e forma) delle schiume in funzione della composizione del precursore. In particolare si e visto che la crescita della schiuma dipende dalla quantita di idruro di titanio, tuttavia superata una certa frazione di TiH2 (0.4% in peso) la densita rimane sostanzialmente costante. Per poter stabilire le condizioni ottimali di processo su una griglia piu fitta di composizioni, limitando il numero di esperimenti da eseguire, sono state implementate due reti neurali artificiali. I risultati mostrano un buon accordo tra i dati sperimentali e i valori calcolati e la differenza e confrontabile con la dispersione dei dati sperimentali. Pertanto, le reti neurali implementate si dimostrano essere un ottimo strumento per l’ottimizzazione dei parametri di processo delle schiume metalliche. Si e poi voluto in particolare analizzare quali fossero le composizioni e le caratteristiche morfologiche piu idonee per avere un migliore assorbimento di energia. Le prove meccaniche statiche e dinamiche indicano chiaramente come il fattore piu importante affinche le schiume possano assorbire energia in un processo di deformazione plastica e la densita. Tanto piu bassa e la densita tanto migliore e il comportamento della schiuma. Per questa ragione schiume di alluminio da applicarsi con la funzione di assorbire urti o smorzare vibrazioni debbono essere a bassa densita e quindi prodotte con una quantita di idruro di titanio uguale o maggiore a 0.4%. Al fine di ottimizzare le prestazioni si dovranno poi scegliere quelle la cui composizione fornisce bolle di dimensione piccola, omogenea e rotonda.

Composites Part B: Engineering, 2005

Fatigue life and endurance limit of Metal Matrix Composites (MMCs), reinforced with ceramic parti... more Fatigue life and endurance limit of Metal Matrix Composites (MMCs), reinforced with ceramic particles, have been remarkably increased by means of thin Ti coatings sputtered at room temperature. The method has been successfully tested for composites of Al alloys (6061, A359, 2618) with different reinforcement particles (Al2O3, SiC). Some alloys were prepared by molten metal process, others by powder metallurgy.

Journal of Nuclear Materials, 2002

Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on ... more Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project – Structural Materials Program.