Analiza prijelomnih površina CuAlNi legura s prisjetljivosti oblika

master's thesis

• Title (english): Analysis of fracture surfaces of the CuAlNi shape memory alloys
• Author: Andrej Vračan
• Mentor: Mirko Gojić (mentor)
• Committee member: Stjepan Kožuh (predsjednik povjerenstva)
• Committee member: Mirko Gojić (član povjerenstva)
• Committee member: Tamara Holjevac-Grgurić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2017-02-24, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy; Physical Metallurgy

Abstract

U ovom radu analizirana je mikrostruktura CuAlNi legure s prisjetljivosti oblika. Ispitivanje
je provedeno na pripremljenim uzorcima u lijevanom i kaljenom stanju. Uzorci su
pripremljeni u vakuum indukcijskoj peći koja je spojena sa uređajem za vertikalno lijevanje.
Postupak lijevanja je proveden u zaštitnoj atmosferi argona, a zatim su pripremljeni za
mikroskopsku analizu brušenjem, poliranjem i nagrizanjem. Mikrostrukturna analiza CuAlNi
legure provedena je svjetlosnim mikroskopom te pretražnim elektronskim mikroskopom.
Rezultati su pokazali da uzorci posjeduju tipičnu martenzitnu mikrostrukturu, a martenzitne
iglice imaju različitu orijentaciju u svakom pojedinom zrnu. Radi ispitivanja mehaničkih
svojstava legure, proveden je statički vlačni pokus, te ispitivanje tvrdoće metodom po
Vickersu. Nakon loma uzorka pri statičnom vlačnom pokusu, provedena je fraktografska
analiza prijelomnih površina CuAlNi legure u lijevanom i kaljenom stanju.

Abstract (english)

In this paper, the microstructure of the CuAlNi shape memory alloy has been analysed.
Examination was conducted on prepared samples in a cast and tempered state. Samples were
produced in a vacuum induction furnace which is connected with a device for vertical casting.
The process was conducted in protective atmosphere of argon, after which they were prepared
for microscopy analysis by grinding, polishing and corrosion. The microstructural analysis of
the CuAlNi shape memory alloy was performed with optical microscopy and scanning
electron microscopy. The results have shown that samples posses a typical martensitic
microstructure. Martensite laths have different orientations inside particular grains. Tensile
testing and hardness testing by the Vickers method were conducted to the determine the
mehanical properties of the CuAlNi shape memory alloy. After the samples fractured during
tensile testing, the analysis of fracture surfaces of the CuAlNi shape memory alloy in cast and
tempered state was conducted.

• Keywords: legure s prisjetljivosti oblika; CuAlNi; mikrostruktura; vertikalno lijevanje; martenzit
• Keywords (english): shape memory alloy; CuAlNi; microstructure; vertical casting; martensite
• Language: croatian
• URN:NBN: urn:nbn:hr:115:156091
• 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: 2017-02-28 08:50:07