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Thesis
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Cercetări privind posibilităţile de îmbunătăţire a caracteristicilor fizico-mecanice şi structurale ale aliajelor de titan prin tratamente de suprafaţă
Epure, Sorin
2009-12-18
Abstract: ABSTRACT În cadrul tezei de doctorat “Cercetari privind posibilitatile de îmbunatatire a caracteristicilor fizicomecanice si structurale ale aliajelor de titan prin tratamente de suprafata“ s-au studiat parametrii si caracteristicile unor faze critice pe fluxul de prelucrare a aliajelor de titan, pentru asigurarea si realizarea în conditii optime a unor tratamente finale de suprafata pe materiale-suport adaptate cerintelor speciale. Concret, pe parcursul întregului flux tehnologic ales (materie prima realizare electrod topire deformare plastica tratament termice prelucrare mecanica tratamente de suprafata), s-au studiat fundamentele teoretice si s-au aplicat programe experimentale pentru evidentierea parametrilor si caracteristicilor care pot influenta major, direct sau indirect, etapele de prelucrare ulterioara si proprietatile finale ori de etapa ale materialului. A fost aplicat un program experimental aplicat Ti si unor aliaje (Ti6Al4V) grupat pe mai multe module, respectiv: determinarea modului de asimilare a elementelor de aliere în cadrul proceselor de retopire a lingourilor, stabilirea influentei atmosferei oxidante la încalzirea aliajelor de titan asupra structurii stratului superficial, evidentierea unor corelatii între cuplul de deformare, temperatura de deformare si intensitatea vitezei de deformatie, prin metoda torsiunii la cald (Capitolul 1), stabilirea metodei/parametrilor de depunere a unor straturi de TiNO prin procedee specifice ingineriei suprafetelor si caracterizarea acestora, precum si stabilirea influentei unor parametri ai procesului de nitrurare în plasma, asupra caracteristicilor fizicomecanice si structurale ale straturilor astfel obtinute (Capitolul 2). Prin evaluarea rezultatelor experimentale în corelatie cu cercetarile fundamentale pe baza datelor oferite de literatura de specialitate s-au identificat factorii de proces cu influenta majora si s-au stabilit variante tehnologice posibile si parametrii de caracterizare pe componentele fluxului de fabricatie a unor produse metalice pe baza de titan: dimensionarea etapei de elaborare a aliajului în corelare cu modul de comportament al elementelor de aliere/impurificare, stabilirea regimurilor de încalzire si deformare plastica la cald, evidentierea parametrilor si caracterizarea functie de destinatie a unor variante de îmbunatatire a caracteristicilor de strat prin metode specifice ingineriei suprafetelor. În finalul lucrarii sunt sumarizate rezultatele obtinute, sunt asamblate pe întregul flux concluziile aplicative si se prezinta posibile directii de continuare a cercetarilor si de dezvoltare a experimentelor. Within the PhD. thesis “Researches on the improvement possibilities of the physico - mechanical and structural characteristics of titan alloys through surface treatments” have been studied the parameters and the characteristics of critical stages of titan alloys processing in order to assure and achieve under optimal conditions some final surface treatments using support-materials which are adapted to special requirements. More specific, during the entire technological process which has been chosen (raw material manufacture of electrode casting-re-casting plastic deformation thermal treatment mechanical processing surface treatment) have been studied the theoretic fundamentals and have been applied experimental programs thus to highlight the parameters and the characteristics that can have a major influence, directly or indirectly, over the subsequent processing stages and the final or stage properties of the material. An experimental program have been applied to Ti and some alloys (Ti6Al4V) grouped on several modules, as follows: determination of the way the alloy elements are assimilated during the re-casting of bars, establishment of the influence of the oxidizing atmosphere at titan alloy heating over the superficial layer structure, highlight the correlations between the deformation couple, deformation temperature and deformation speed intensity, using the heat torsion method (Chapter 1), establishment of the deposition method/parameters of TiNO layers using surface engineering specific procedures and its characterization, as well as establishment of some parameters influence of plasma nitridation process over the physico - mechanical and structural characteristics of the layers obtained in this way (Chapter 2). By evaluating the experimental results in correlation with fundamental researches on the basis of the data provided by the specialty literature have been identified process factors with major influence and have been established possible technological versions and characterization parameters on process components of some metallic products based on titan: the size of the alloy elaboration stage in correlation with the behavior of the alloy/impure elements, establishment of the heating and heat plastic deformation conditions, highlight the parameters and characterize, depending on destination, some improvement ways of layers characteristics through surface engineering specific methods. In the end of the thesis are summarized the obtained results, assembled the applicative conclusions of the entire process and presented the possible directions on which the researches can be carried out and on which the experiments can be developed.
Keyword(s): Titan -- Aliaje -- Teză de doctorat ; Metalurgie neferoasă -- Teză de doctorat
OPAC: See record in BC-UPB Web OPAC
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Notice créée le 2016-09-16, modifiée le 2016-09-16
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