Ternarni sistem Al-Cr-Sc

magistrsko delo

Monika Kušter (Avtor), Boštjan Markoli (Mentor), Sašo Šturm (Komentor)

Povzetek

V magistrskem delu je opisana izdelava, priprava ter analiza binarnih in ternarnih zlitin med čistimi elementi aluminija, kroma in lahko redko zemljo, skandijem. Na začetku je podan literaturni pregled binarnih robnih sistemov Al-Cr, Al-Sc in Cr-Sc ter pojasnitev osnovnih pojmov faznih diagramov, njihove namembnosti in opis faznih reakcij ter transformacij, ki se pojavijo v omenjenih robnih sistemih. Zlitine so bile izdelane z vakuumskim obločnim taljenjem v inertni atmosferi argona ter homogenizacijskim žarjenjem pri 950 °C in 990 °C ter času 240 ur in 500 ur. Za karakterizacijo mikrostrukturnih sestavin v zlitinah in mikrokemijsko analizo so bile uporabljene preiskave strukture in sestave zlitin kot, optična mikroskopija za prvi vpogled v mikrostrukturo (SM), vrstična elektronska mikroskopija (SEM) z energijsko disperzijskim spektrometrom rentgenskih žarkov (EDS) s katerim se je opravila kemijska analiza nastalih faz. Najbolj pomembna uporabljena metoda je bila rentgenska fazna in strukturna anliza (XRD) s katero smo identificirali vse nastale faze v zlitinah in jim pripisali ustrezne kristalne strukture. Dobljene osnovne celice kristalnih struktur smo prilagodili z Rietveldovo metodo glede na naše eksperimentalne difraktograme. Diferenčna vrstična kalorimetrija (DSC) nam je bila v pomoč pri preučevanju faznih prehodov v zlitinah. S pomočjo vseh uporabljenih eksperimentalnih metod smo odkrili do sedaj še nepoznano ternarno fazo. Ternarna faza, ki se je pojavila v vseh izdelanih ternarnih zlitinah z različno začetno sestavo in do sedaj še ni bila raziskana, je heksagonalnega strukturnega tipa s prostorsko skupino P63/mmc in s sestavo Al od 48,0 do 58,0 at. %, Cr od 8,0 do 18,0 at. % in Sc od 33,0 do 34,0 at. % ter jo lahko uvrstimo med Lavesove faze.

Ključne besede

aluminijeve zlitine;ternarni sistem;mikrostruktura;karakterizacija;metoda XRD;kristalna struktura;

Podatki

Jezik:	Slovenski jezik
Leto izida:	2018
Tipologija:	2.09 - Magistrsko delo
Organizacija:	UL NTF - Naravoslovnotehniška fakulteta
Založnik:	[M. Kušter]
UDK:	669
COBISS:	1750623
Št. ogledov:	1067
Št. prenosov:	343
Ocena:	0 (0 glasov)
Metapodatki:

Ostali podatki

Sekundarni jezik:	Angleški jezik
Sekundarni naslov:	ternary system Al-Cr-Sc
Sekundarni povzetek:	In this master's degree thesis the preparation and analyses of binary and ternary alloys between pure elements of aluminium, chromium and light rare earth, scandium is presented. Literature review of binary systems Al-Cr, Al-Sc and Cr-Sc is given, as well as classification of basic concepts of phase diagrams, their importance and description of the phase reactions and transformations that occurs in the mentioned systems. Alloys were made by vacuum arc melting in an inert atmosphere of argon, fallowed by homogenization annealing at 950 ° C and 990 ° C for 240 hours and 500 hours. Various methods were used for characterization of microstructural components in alloys and for microchemical analysis. Optical microscopy for the first insight into the microstructure, a scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) for analysing the chemical composition of detected phases in microstructure. The most important method that was used is X-ray powder diffraction (XRD), with which we identified all the phases in alloys and determined their crystal structure. Crystal structures were adapted with the Rietveld method to our experimental diffractogram. Differential scanning calorimetry (DSC) were used for all aloys where new ternary phase was detected and with DCS we investigated phase transitions in alloys. The new ternary phase, which appeared in all made ternary alloys and which has not yet been studied, has a hexagonal crystal structure with space group P63/mmc and with composition of Al from 48,0 to 58,0 at. %, Cr from 8,0 to 18,0 at. % and Sc from 33,0 to 34,0 at. % and it is predicted to be Laves phase.
Sekundarne ključne besede:	aluminium alloys;ternary system;microstructure;characterization;XRD;crystal structure;
Vrsta dela (COBISS):	Diplomsko delo/naloga
Študijski program:	0
Komentar na gradivo:	Univ. v Ljubljani, Naravoslovnotehniška fak. , Odd. za materiale in metalurgijo
Strani:	XIV, 77 f.
ID:	10961111