Utjecaj toplinske obrade na svojstva aluminijske legure AlSi1MgMn

master's thesis

• Title (english): Influence of heat treatment on the properties of AlSi1MgMn aluminum alloy
• Author: Domagoj Fekonja
• Mentor: Darko Landek (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-03-31, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu je opisana toplinska obrada precipitacijski očvršćivih aluminijevih legura te njezin utjecaj na mikrostrukturu i svojstva legura. S odabirom parametara toplinske obrade postižu se različite vrijednosti dobivenih parametara ispitivanja kao i dobivene mikrostrukture koje značajno utječu na kvalitetu postignutog stanja materijala. U eksperimentalnom dijelu rada određena je tvrdoća i otpornost na koroziju uzoraka aluminijeve legure AlSi1MgMn koji su različito toplinski obrađivani. Toplinska obrada sastojala se od homogenizacijskog žarenja te umjetnog starenja, pri čemu su varirani parametri hlađenja te temperatura i vrijeme umjetnog starenja. Ispitivanjem tvrdoće nakon umjetnog starenja dobiven je raspon tvrdoća, pri čemu je najveća postignuta vrijednost iznosila 146 HV1, dok je najmanja bila 90 HV1. Elektrokemijska ispitivanja pokazala su da je kod svih ispitnih uzoraka došlo do značajne pojave rupičaste korozije u vodenoj otopini 3,5 % NaCl uz razaranje pasivnog filma ubrzo nakon kontakta aluminijeve legure s otopinom. Analizom mikrostrukture utvrđeno je poželjno stanje legure, gdje su sitne precipitacijske čestice homogeno raspoređene u aluminijevoj matrici, a vidljiva je i prisutnost pora i mikropukotina pri povećanjima većim od 500x. Najveća otpornost na koroziju i povišena tvrdoća postignuta je nakon rastvornog žarenja, hlađenja u vodi temperature 50 °C i umjetnog starenja s parametrima 150 °C/10 h/zrak.

Abstract (english)

The paper describes the heat treatment of precipitation hardening aluminum alloys and its impact on the microstructure and properties of alloys. By choosing the heat treatment parameters, different values of the obtained test parameters, as well as the obtained microstructures are achieved, which significantly affect the quality of the achieved state of the material. In the experimental part, the hardness and corrosion resistance of aluminum alloy AlSi1MgMn samples that were differently heat treated were determined. Heat treatment consisted of homogenization annealing and artificial aging, with varying cooling parameters and also varying temperature and time of the artificial aging. Hardness testing after artificial aging gave a range of hardnesses, with the highest value of 146 HV1, while the lowest was 90 HV1. Electrochemical tests showed that on all testing speciments significant pitting corrosion in aqueous 3,5 % NaCl solution has appeared, with destruction of the passive film shortly after the aluminum alloy was in contact with the solution. By the microstructure analysis the preffered state of the alloy was determined, where small precipitation particles are homogeneously distributed in the aluminum matrix. The presence of pores and microcracks at the magnifications greater than 500x is visible. The highest corrosion resistance and increased hardness was achieved after solution annealing, cooling into water at 50 °C and with artificial aging parameters 150 °C/10 h/air.

• Keywords: precipitacijsko očvršćivanje; aluminijeva legura AlSi1MgMn; toplinska obrada; tvrdoća; elektrokemijska korozija; mikrostrukturna analiza
• Keywords (english): precipitation hardening; aluminum alloy AlSi1MgMn; heat tretment; hardness; electrochemical corrosion; microstructure analysis
• Language: croatian
• URN:NBN: urn:nbn:hr:235:151300
• Study programme: Title: Mechanical Engineering; specializations in: Design, Process and Energy Engineering, Production Engineering, Engineering Modelling and Computer Simulation, Marine Engineering, Industrial Engineering and Management, Materials Engineering, Mechatronics and Robotics, Autonomous Systems; Course: Materials Engineering; Study programme type: university; Study level: graduate; Academic / professional title: magistar/magistra inženjer/inženjerka strojarstva (magistar/magistra inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access; Embargo expiration date: 2024-03-24
• Created on: 2022-03-24 16:09:00