Utjecaj usitnjavanja zrna al legure na svojstva odljevaka

master's thesis

• Title (english): Effect of al alloy grain refinement on the properties of cast part
• Author: Ivan Vidović
• Mentor: Branko Bauer (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2016-07-14, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering; Production Mechanical Engineering

Abstract

U okviru ovog rada opisano je usitnjavanje zrna kod lijevanja aluminijskih legura. Rad se sastoji od teorijskog i eksperimentalnog dijela.
U teorijskom dijelu ukratko je objašnjeno lijevanje i postupci lijevanja, također je opisan aluminij i njegove legure. Prikazan je pregled osnovnih teorija skrućivanja metala i legura, mehanizama nukleacije, odnosno započinjanja procesa skrućivanja te mehanizama rasta kristala. Objašnjen je postupak obrade taljevine usitnjavanjem zrna aluminijskih legura. Ukratko su objašnjene predlegure za usitnjavanje zrna te karakteristike i svojstva njima obrađene taljevine.

U eksperimentalnom dijelu rada ispitivan je utjecaj usitnjavanja zrna aluminijske legure AlSi12. Cilj je bio utvrditi učinak usitnjavanja zrna predlegurom AlTi5B1 kao i različitih brzina hlađenja na mikrostrukturu i mehanička svojstva navedene legure. U tu svrhu provedeno je lijevanje osnovne AlSi12 legure i AlSi12 legure obrađene AlTi5B1 predlegurom. Pripremljeni su uzorci i epruvete te su provedena metalografska i mehanička ispitivanja.

Na temelju dobivenih rezultata pokazalo se da usitnjavanje zrna predlegurom AlTi5B1 povoljno utječe na mikrostrukturu legure, ali dolazi do smanjenja mehaničkih svojstava i istezljivosti.

Abstract (english)

Grain refinement of cast aluminum alloy was investigated and described in theoretical and experimental part of this paper.
Theoretical part explains casting, casting processes as well as aluminum and it's alloys. Metal and alloy solidification theories, nucleation and crystal growth mechanisms are reviewed. Grain refinement of liquid metal is explained. Short review of grain refinemet master alloys and their effects on aluminum alloys is presented.

Influence of grain refinement on AlSi12 alloy was investigated within experimental part of this paper. Objective was to determine the influence of AlTi5B1 grain refinement and cooling rates on microstructure and mechanical properties of alloy examined. For this purpose base alloy AlSi12 as well as AlTi5B1 refined AlSi12 alloy were cast. Test specimens for micrography and mechanical testing were examined.

Results showed that AlTi5B1 grain refinement had positive influence on microstructure, but mechanical properties and elongation values were lowered.

• Keywords: AlSi12 legura; skrućivanje; usitnjavanje zrna; mikrostruktura; mehanička svojstva
• Keywords (english): AlSi12 alloy; solidification; grain refinement; microstructure; mechanical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:235:607574
• Study programme: Title: Mechanical 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
• Created on: 2019-05-22 17:02:21