Mikrostrukturna analiza CuAlMn legure s prisjetljivosti oblika

master's thesis

• Title (english): Microstructural analysis of CuAlMn alloy with shape memory effect
• Author: Dino Bajutti
• Mentor: Ivana Ivanić (mentor)
• Committee member: Stjepan Kožuh (predsjednik povjerenstva)
• Committee member: Ivana Ivanić (član povjerenstva)
• Committee member: Mirko Gojić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2022-08-31, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy

Abstract

U ovom radu provedena je mikrostrukturna analiza CuAlMn legure kemijskog sastava Cu – 8,2% Al – 8,3% Mn (mas %). Dobivena legura s prisjetljivosti oblika podvrgnuta je postupku kovanja i toplinske obrade. Toplinska obrada šipke nakon kovanja promjera 13 – 14 mm sastojala se od žarenja 870 °C/20 minuta uz hlađenje u pijesku i od žarenja na 870 °C/20 minuta uz hlađenje u vodi. Mikrostrukturna analiza lijevanog stanja CuAlMn legure provedena je optičkom i pretražnom elektronskom mikroskopijom te energetsko disperzijskom spektroskopijom. Nakon kovanja i toplinske obrade mikrostrukturna analiza provedena je optičkom mikroskopijom. Rezultati su pokazali kako je mikrostruktura CuAlMn legure žarene na 870 °C/20´ i hlađene u pijesku krupnozrnata dvofazna (α+β), dok je mikrostruktura CuAlMn legure žarene na 870 °C/20´ i hlađene u vodi krupnozrnata martenzitna mikrostruktura. Putem optičke mikroskopije primjećene su pukotine u CuAlMn leguri. Ispitivanje makrotvrdoće provedeno je Brinell-ovom metodom, a rezultati pokazuju niže vrijednosti makrotvrdoće pri hlađenju u vodi za razliku od hlađenja u pijesku.

Abstract (english)

In this work, a microstructural analysis of CuAlMn alloy with chemical composition Cu - 8.2% Al - 8.3% Mn (wt.%) was performed. The resulting shape memory alloy was subjected to a forging and heat treatment process. The heat treatment of the bar after forging with a diameter of 13 – 14 mm consisted of annealing at 870 °C/20 minutes with cooling in sand and of annealing at 870 °C/20 minutes with cooling in water. Microstructural analysis of the as cast state of CuAlMn alloy was performed by optical and scanning electron microscopy and energy dispersive spectroscopy. After forging and heat treatment, microstructural analysis was performed by optical microscopy. The results showed that the microstructure of CuAlMn alloy annealed at 870 °C/20´ and cooled in sand has a large grained two phases (α+β), while the microstructure of CuAlMn alloy annealed at 870 °C /20´ and cooled in water was a large grained martensitic microstructure. Cracks in the CuAlMn alloy were observed by optical microscopy. The macrohardness test was performed by the Brinell method, and the results show lower values of macrohardness during cooling in water unlike cooling in sand.

• Keywords: legure s prisjetljivosti oblika; CuAlMn legura; martenzit; toplinska obrada; mikrostruktura; makrotvrdoća
• Keywords (english): shape memory alloy; CuAlMn alloy; martensite; heat treatment; microstructure; macrohardness
• Language: croatian
• URN:NBN: urn:nbn:hr:115:846815
• 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: 2022-08-21 15:25:51