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doctoral thesis
THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER
2023. urn:nbn:hr:190:938507
Liverić, Lovro
University of Rijeka
Faculty of Engineering

Cite this document

Liverić, L. (2023). THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER (Doctoral thesis). Rijeka: University of Rijeka, Faculty of Engineering. Retrieved from https://urn.nsk.hr/urn:nbn:hr:190:938507

Liverić, Lovro. "THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER." Doctoral thesis, University of Rijeka, Faculty of Engineering, 2023. https://urn.nsk.hr/urn:nbn:hr:190:938507

Liverić, Lovro. "THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER." Doctoral thesis, University of Rijeka, Faculty of Engineering, 2023. https://urn.nsk.hr/urn:nbn:hr:190:938507

Liverić, L. (2023). 'THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER', Doctoral thesis, University of Rijeka, Faculty of Engineering, accessed 03 April 2025, https://urn.nsk.hr/urn:nbn:hr:190:938507

Liverić L. THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER [Doctoral thesis]. Rijeka: University of Rijeka, Faculty of Engineering; 2023 [cited 2025 April 03] Available at: https://urn.nsk.hr/urn:nbn:hr:190:938507

L. Liverić, "THE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER", Doctoral thesis, University of Rijeka, Faculty of Engineering, Rijeka, 2023. Available at: https://urn.nsk.hr/urn:nbn:hr:190:938507

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Metadata
TitleTHE DEVELOPMENT OF Cu-BASED SHAPE MEMORY ALLOYS MICROALLOYED WITH SILVER
Title (croatian)RAZVOJ LEGURA S EFEKTOM PRISJETLJIVOSTI OBLIKA NA BAZI BAKRA MIKROLEGIRANIH SREBROM
AuthorLovro Liverić
MentorTamara Holjevac Grgurić (mentor)
MentorSunčana Smokvina Hanza (komentor)
MentorWojciech Sitek https://orcid.org/0000-0002-6564-7177 (komentor)
Committee memberDario Iljkić (predsjednik povjerenstva)
Committee memberMatej Fonović (član povjerenstva)
Committee memberEmi Govorčin-Bajsić (član povjerenstva)
GranterUniversity of Rijeka
Faculty of Engineering
Rijeka
Defense date and country2023-11-14, Croatia
Scientific / art field,
discipline and subdiscipline		TECHNICAL SCIENCES
Mechanical Engineering
Universal decimal classification
(UDC)		62 - Engineering. Technology in general
Abstract
In the thesis, the influence of silver addition on martensite formation, phase transformation temperatures, and functional properties of Cu-based shape memory alloys is investigated. Microstructural analysis of quaternary Cu-Al-Mn-Ag and ternary Cu-Al-Ag SMA alloys was carried out by optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and transmission electron microscopy (TEM). Phase identification was further confirmed by X-ray... More diffraction analysis and high-energy synchrotron (XRD). Martensitic transformation temperatures and fusion enthalpies were observed by modular differential scanning calorimetry (MDSC), while microhardness was determined by Vickers test. The results show that silver additions significantly influenced formations of the martensite structure, even in the as-cast state and especially after heat treatment and quenching in both investigated systems. Cu-9Al-16Mn-2Ag and Cu-9Al-7Mn with 2 and 5% wt. of silver showed the best functional properties, forming two types of martensite structures β1’ (18R) and γ1’ (2H). Optimal compositions of Cu-Al-Ag ternary SMA alloys forming best functional properties were found in alloys with 5 and 7% wt. of silver, with one type of martensitic structure β1’ (18R) identified. Less
Abstract (english)
Legure s efektom prisjetljivosti oblika (SMA) su pametni funkcionalni materijali koji posjeduju dva jedinstvena efekta, efekt prisjetljivosti i pseudoelastičnosti te pokazuju sposobnost povrata definiranog oblika djelovanjem temperature ili mehaničkog naprezanja. Komercijalno najkorištenija, ali istovremeno i najskuplja legura, je nitinol (Ni-Ti). U posljednje vrijeme nitinol se sve više zamjenjuje legurama na bazi bakra, koje imaju odlična funkcionalna i električna svojstava,... More jednostavniju proizvodnju i nižu cijenu koštanja. Od legura na bazi bakra najviše se koriste Cu-Al-Ni i Cu-Zn-Al SMA legure, koje su istraživane dugi niz godina, no pokazale su ograničenje u primjeni s obzirom na vrlo visoku krtost i lošija mehanička svojstva. Dodavanjem mangana binarnoj Cu-Al leguri, poboljšava se duktilnost i sposobnost hladne obradivosti materijala jer mangan proširuje područje β-faze u nižim udjelima aluminija. Dizajniranjem sastava ternarnih legura s prisjetljivošću oblika te mikrolegiranjem četvrtom komponentom, moguće je znatno promijeniti svojstva legura te korigirati temperature transformacija i prilagoditi ih specifičnom području primjene. Rezultati doktorskog istraživanja pokazuju da dodatak srebra značajno utječu na formiranje martenzitne strukture, čak i u lijevanom stanju, a posebno se intenzivni martenzit formira nakon toplinske obrade i kaljenja u oba istraživana sustava. Kod četverokomponentnih sustava, sastavi Cu-9Al-7Mn s 2 i 5% mas. Ag te Cu-9Al-16Mn-2Ag pokazali su najbolja funkcionalna svojstva materijala. U svim istraživanim sustavima javlja se samo jedan tip martenzita, β1’ (18R), izuzev u sustavima s 16% mas. Mn i 2% mas. Ag, gdje su utvrđene dvije različite metastabilne martenzitne strukture, β1’ (18R) i γ1’ (2H). Dodavanjem srebra, temperature početka martenzitne transformacije, Ms, pomiču se prema višim vrijednostima, uz istovremeno proširenje područja formiranja martenzita veće entalpije te niže temperature završetka transformacije, Mf. Toplinska obrada dodatno povisuje temperaturu Ms. Legure koje u sastavu sadrže 10% mas. Mn i različite udjele srebra, u mikrostrukturnim analizama nisu pokazale prisutnost martenzita, što može ukazivati na vrlo niske temperature početka martenzitne transformacije, znatno niže od sobne temperature. Cu-Al-Mn-Ag legure nakon kaljenja pokazuju nižu mikrotvrdoću, što je tipično za SMA sustave. Legura s 16% mas. Mn pokazuje povećanje mikrotvrdoće nakon toplinske obrade, što može biti posljedica prisustva krte γ1’ (2H) faze u mikrostrukturi ove legure. Kod ternarnih sustava, najintenzivniji martenzit i najbolja svojstva pokazale su legure s 5 i 7% mas. Ag. Less
Keywords
Keywords (english)
Languagecroatian
URN:NBNurn:nbn:hr:190:938507
Promotion2023
Study programmeTitle: Postgraduate university (doctoral) study
Study programme type: university
Study level: postgraduate
Academic / professional title: doktor/doktorica znanosti, područje tehničkih znanosti (doktor/doktorica znanosti, područje tehničkih znanosti)
Type of resourceText
ExtentV, 149 str.: 30 cm
File originBorn digital
Access conditionsOpen access
Terms of useLicence Attribution 4.0 International (CC BY 4.0) icon
Created on2023-11-27 12:13:42
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