Analysis of geometrical characteristics of pulsed nd:yag laser drilled holes in superalloy nimonic 263 sheets

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd(3+):YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes

Analiza geometrijskih značajki rupa bušenih ND:YAG impulsnim laserom u limovima superlegure Nimonik 263

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd3+:YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes.Zbog svojih odličnih mehaničkih i fizikalnih značajki, superlegure su najpogodniji materijal za uporabu u toplim sekcijama zrakoplovnih motora. U konstrukcijskim dijelovima strojeva treba izbušiti tisuće rupa, za što se kao najučinkovitija pokazala laserska tehnika. Bušenje laserom koristi se za proizvodnju malih promjera, točno pozicioniranih rupa, s malim oštećenjima u području oko njih i u različitim materijalima. Učinkovita uporaba lasera za bušenje rupa visoke kvalitete za kritične primjene uvelike ovisi o ispravnom izboru i optimiranju parametara bušenja laserom. U ovom radu, rupe su izbušene Nd3+:YAG impulsnim laserom, uz maksimalnu prosječnu snagu od 160 W, u limovima superlegure nikla Nimonic 263, debljine 0,7 mm i 1,2 mm. Rupe su promatrane optičkim i skenirajućim elektronskim mikroskopom. Istražene su i analizirane geometrijske značajke laserski bušenih rupa, koje ovise o parametrima lasera. Cilj ovog istraživanja bio je pronaći optimalne parametre lasera koji bi omogućili što pravilnije rupe.[http://www.tehnicki-vjesnik.com

Femtosecond Laser Interaction with Nickel Based Superalloy M-252

Nickel-base superalloys are an important class of engineering materials designed for high - temperature applications such as aero-engine components. Good corrosion resistance, optimal thermal properties, strength coupled with ductility, creep and fatigue resistance, as well as optimal impact and wear resistance are the main requirements for a satisfactory function in such severe environments at high temperatures. Lasers have been used for high precision material processing in micro- and nanomanufacturing operations due to the specific nature of the light that they emit, such as the high intensity and the possibility of controlled surface modification. In the last few decades a lot of attention was paid to surface modifications of different metals and their alloys by various types of laser light. Treatment of superalloys’ surfaces with laser light can induce the changes in the microstructure which result in improved mechanical properties of the material. In this work, the process of interaction is related to exposure of nickel superalloy M-252 to femtosecond laser beam. The effect of the laser beams on the surface of the multicomponent alloys is performed by different pulse energies and different exposition time. The changes in the microstructure, depending on the parameters of the laser beam, are identified by the scanning electron microscope (SEM) and energy-dispersive spectrometry (EDS), and the mean grain size was measured by the method of the circle. The aim of the study was to optimize the parameters of laser treatment to reach the microstructure with the favourably affects for the surface quality

Primena metode konačnih elemenata na simulaciju procesa livenja

One of the biggest problems in the process of casting, is how to determine the distribution of temperature, taking into consideration the effects of several mechanisms of heat exchange. The experimental methods being rather expensive and complicated, the numerical methods are nowadays applied largely. Differential equations of heat conduction are derived according to the basic laws of continuum mechanics, taking into account the phase changes during the casting. The equations obtained are solved by the method of finite elements. In this way, a new scientific discipline is established within the scope of continuum mechanics. As an application of the described procedure, the temperature fields in the casting process of alloyed casting are determined.Jedan od najsloženijih problema pri livenju je kako i na koji način da se odredi raspodela temperature, obzirom na dejstvo više mehanizama razmene toplote. Kako su eksperimentalne metode dosta skupe i složene, u novije vreme veliku primenu imaju numeričke metode. Polazeći od osnovnih zakona mehanike kontinuuma definisane su diferencijalne jednačine provođenja toplote, uzimajući u obzir fazne promene pri livenju. Dobijene jednačine su rešavane metodom konačnih elemenata. Time je ustanovljena nova naučna disciplina u okviru mehanike kontinuuma. Kao primena opisane procedure određena su temperaturna polja u toku procesa livenja legiranog liva

Primena metode konačnih elemenata na simulaciju procesa livenja

One of the biggest problems in the process of casting, is how to determine the distribution of temperature, taking into consideration the effects of several mechanisms of heat exchange. The experimental methods being rather expensive and complicated, the numerical methods are nowadays applied largely. Differential equations of heat conduction are derived according to the basic laws of continuum mechanics, taking into account the phase changes during the casting. The equations obtained are solved by the method of finite elements. In this way, a new scientific discipline is established within the scope of continuum mechanics. As an application of the described procedure, the temperature fields in the casting process of alloyed casting are determined.Jedan od najsloženijih problema pri livenju je kako i na koji način da se odredi raspodela temperature, obzirom na dejstvo više mehanizama razmene toplote. Kako su eksperimentalne metode dosta skupe i složene, u novije vreme veliku primenu imaju numeričke metode. Polazeći od osnovnih zakona mehanike kontinuuma definisane su diferencijalne jednačine provođenja toplote, uzimajući u obzir fazne promene pri livenju. Dobijene jednačine su rešavane metodom konačnih elemenata. Time je ustanovljena nova naučna disciplina u okviru mehanike kontinuuma. Kao primena opisane procedure određena su temperaturna polja u toku procesa livenja legiranog liva

ANALIZA SPECIFIČNIH ODBOJKAŠKIH AKCIJA I KLASIFIKACIJA NJIHOVIH TEHNIČKO - TAKTIČKIH VARIJANTI

The classification of technical and tactical variables enables to discover the cau- ses of modern volleyball’s (trendy volleyball) beginning and makes the experts to dedica- te themselves to discovering new innovation methods for first - class volleyball players’ training. This kind of methods would contribute to variety and imagination of the future volleyball that is going to be much more interesting. Anyway, there is also a possibility of changing some game rules and getting back the spirit of outplay by giving the equal rights to the attack players as well as to the defence players

ODREĐIVANJE TIPOLOGIJE IGRE VRHUNSKIH REPREZENTACIJA PUTEM ODBOJKAŠKIH KANONA

The lack of theoretical thought in volleyball makes it hard to use and develop specialties in style of great masters in modern outplay. The peculiarity and the excepti- onality are not noticed and recognized enough and, if it even happens to get discovered, they are not classified so they can not be the real values during the further shaping. By the time the impressions (that are not going further than fascination and inspiration of a moment) are fading and disappearing as well as their carriers. The examples of that kind of “disappearing” are numerous in volleyball practise

Analiza geometrijskih značajki rupa bušenih ND:YAG impulsnim laserom u limovima superlegure Nimonik 263

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd3+:YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes.Zbog svojih odličnih mehaničkih i fizikalnih značajki, superlegure su najpogodniji materijal za uporabu u toplim sekcijama zrakoplovnih motora. U konstrukcijskim dijelovima strojeva treba izbušiti tisuće rupa, za što se kao najučinkovitija pokazala laserska tehnika. Bušenje laserom koristi se za proizvodnju malih promjera, točno pozicioniranih rupa, s malim oštećenjima u području oko njih i u različitim materijalima. Učinkovita uporaba lasera za bušenje rupa visoke kvalitete za kritične primjene uvelike ovisi o ispravnom izboru i optimiranju parametara bušenja laserom. U ovom radu, rupe su izbušene Nd3+:YAG impulsnim laserom, uz maksimalnu prosječnu snagu od 160 W, u limovima superlegure nikla Nimonic 263, debljine 0,7 mm i 1,2 mm. Rupe su promatrane optičkim i skenirajućim elektronskim mikroskopom. Istražene su i analizirane geometrijske značajke laserski bušenih rupa, koje ovise o parametrima lasera. Cilj ovog istraživanja bio je pronaći optimalne parametre lasera koji bi omogućili što pravilnije rupe

Niskougljenični čelici i promene u njihovoj strukturi nastale laserskim zračenjem u dva režima rada

In this paper low-carbon steel which 3,8-4,2% Si and 0,08% C transformer plates exposed to the radiation of ruby laser in Q-switch and free generation regimes are examined. Investigations were carried out at atmospheric pressure under the laboratory conditions. Transformer plates were subjected to very high temperature gradients under heating and cooling conditions where the former is correlated to pulse characteristic and the later to material. Preliminary investigations were carried out by laser drilling and resulting traces on material were recorded by scanning electron microscope to find out the influence of different energies and pulse lengths on structural changes in the material, but wide application of transformer plates in electrical and mechanical engineering demands finding the regimes of thermomechanical processing and also the technology of cutting and connecting in the sense of conservation of magnetic characteristics.U ovom radu ispitivanja su izvedena na niskougljeničnim čelicima sa 3,8-4,2% Si i 0,08% S koji su izlagani dejstvu rubinskog lasera u režimu gigantskih impulsa (Q-switch) i slobodne generacije. Ispitivanja su izvedena na atmosferskom pritisku u laboratorijskim uslovima. Transformatorski limovi su podvrgavani vrlo velikim temperaturnim gradijentima u uslovima grejanja i hlađenja, od kojih je prvi vezan za karakteristiku impulsa, a drugi za materijal. Preliminarna ispitivanja izvedena su bušenjem laserskim snopom, a ostvareni otisci na materijalu snimani su skaning elektronskim mikroskopom s ciljem da se definiše uticaj različitih energija i vremena impulsa na strukturne promene u materijalu, jer velika primena niskougljeničnih čelika sa 3,8-4,2% Si i 0,08% S u elektronici i mašinstvu zahteva definisanje režima termomehaničke obrade, a takođe i tehnologiju rezanja i spajanja u smislu očuvanja magnetnih karakteristika

Analiza geometrijskih značajki rupa bušenih ND:YAG impulsnim laserom u limovima superlegure Nimonik 263

Owing to their excellent mechanical and physical characteristics, superalloys are the most suitable material for use in hot sections of aircraft engines. Thousands of holes need to be drilled in constructive parts of machines, with laser technique emerging as the most effective. Laser drilling has been used to produce small diameter, accurately positioned holes, with little damage in regions around them, and in various materials. Effective laser employment of drilling of high quality holes for critical applications highly depends on correct selection and optimization of laser drilling parameters. In this work, the holes were drilled by a pulsed Nd3+:YAG laser, with maximum average power of 160 W, in superalloy Nimonic 263 sheets, thickness 0,7 mm and 1,2 mm. The holes were observed by optical and scanning electron microscope. Geometrical characteristics of laser drilled holes that depend on laser parameters were investigated and analysed. The aim of this investigation was to find optimal laser parameters which would produce as much as possible regular holes.Zbog svojih odličnih mehaničkih i fizikalnih značajki, superlegure su najpogodniji materijal za uporabu u toplim sekcijama zrakoplovnih motora. U konstrukcijskim dijelovima strojeva treba izbušiti tisuće rupa, za što se kao najučinkovitija pokazala laserska tehnika. Bušenje laserom koristi se za proizvodnju malih promjera, točno pozicioniranih rupa, s malim oštećenjima u području oko njih i u različitim materijalima. Učinkovita uporaba lasera za bušenje rupa visoke kvalitete za kritične primjene uvelike ovisi o ispravnom izboru i optimiranju parametara bušenja laserom. U ovom radu, rupe su izbušene Nd3+:YAG impulsnim laserom, uz maksimalnu prosječnu snagu od 160 W, u limovima superlegure nikla Nimonic 263, debljine 0,7 mm i 1,2 mm. Rupe su promatrane optičkim i skenirajućim elektronskim mikroskopom. Istražene su i analizirane geometrijske značajke laserski bušenih rupa, koje ovise o parametrima lasera. Cilj ovog istraživanja bio je pronaći optimalne parametre lasera koji bi omogućili što pravilnije rupe.[http://www.tehnicki-vjesnik.com