Termodinamičko modeliranje Cu-Al-Mn-Ag legura

master's thesis

• Title (english): Thermodinamic modelling of Cu-Al-Mn-Ag alloys
• Author: Franko Mlinarić
• Mentor: Ivan Brnardić (mentor)
• Committee member: Anita Štrkalj (predsjednik povjerenstva)
• Committee member: Ivan Brnardić (član povjerenstva)
• Committee member: Tamara Holjevac Grgurić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2021-07-22, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy

Abstract

Cu-Al-Mn legure s prisjetljivošću oblika (Cu-SMA) sve se više koriste kao zamjena vrlo skupim legurama na bazi Ni-Ti, nitinola, no uglavnom u području elektronike i drugih industrija, nešto manje u bioinženjerstvu, s obzirom da biokompatibilnost nitinola još uvijek nema kvalitetnu zamjenu. Efekt prisljetljivosti oblika posljedica je bezdifuzijske martenzitne transformacije, koja podrazumjeva rekristalizacijski proces u čvrstom stanju.
Osnova svih SMA legura na bazi bakra su binarni sustavi Cu-Al i Cu-Zn te se dodavanjem daljnjih komponenti definiraju svojstva prisjetljivosti oblika (SE), mehanička svojstva i temperature transformacija. Dodavanjem mangana osnovnoj binarnoj Cu-Al leguri,proširuje se područje -faze, a time se povećava duktilnost materijala, kao i svojstvo hladnogdeformiranja materijala.
U ovom radu istražen je utjecaj srebra na mikrostrukturu i temperature faznih transformacija ternarnih Cu-Al-Mn legura. Cu-Al-Mn-Ag legure pripremljene su taljenjem u elektrolučnoj peći. Proveden je termodinamički proračun programom Thermo-Calc te su određene temperature transformacija Cu-Al-Mn-Ag legura, dinamičkim mjerenjima kroz 5 ciklusa zagrijavanja/hlađenja. Mikrostrukturna ispitivanja provedena su skenirajućom elektronskom mikroskopijom(SEM). Rezultati mikrostrukture korelirani su s promjenom sastava Cu-Al-Mn-Ag legure i udjelom srebra te pomakom temperatura transformacija.

Abstract (english)

Cu-SM Ashape memory alloys became very attractive for commercial use and they are frequently used instead of very expensive Ni-Ti alloy,mostly in electronic and other industries due to still irreplaceable biocompatible properties of nitinol. Shape memory effect is a consequence of the diffusionless martensitic transformation, which implies a change of crystal structure. All Cu-SMA alloys are based on binary Cu-Al and Cu-Zn systems. Addition of manganese to binary Cu-Al alloy, broadens-phase region, increases ductility and cold workability of material.
In this paper, the effect of silver addition on the microstructure and transformation temperatures of Cu-Al-Mn alloys was investigated. Cu-Al-Mn-Ag alloys were prepared by melting in the electric-arc furnace. Thermodynamic calculation and solidification mechanism was performed by software Thermo-Calc 5 and transformation temperatures of Cu-Al-Mn-Ag alloys were carried out through two dynamic cycles in DSC. Microstructural investigations were performed by scanning electron microscopy (SEM). Microstructural results were correlated with silver content in Cu-Al-Mn-Ag alloy as well as transformation temperatures.

• Keywords: Cu-Al-Mn-Ag legure; efekt prisjetljivosti oblika; fazne transformacije; martenzit; DSC analiza
• Keywords (english): Cu-Al-Mn-Ag alloys; shape memory effect; phase transformations; martensitic structure; DSC analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:115:247499
• Study programme: Title: Graduate study program Metallurgy; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka metalurgije (magistar/magistra inženjer/inženjerka metalurgije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2021-07-22 11:35:43