Utjecaj tehnološke obrade taline na razvoj mikrostrukture i mehaničkih svojstava AlSi12 legure

master's thesis

• Title (english): The influence of melt processing on microstructure and mechanical properties of AlSi12 alloy
• Author: Barbara Tubić
• Mentor: Zdenka Zovko Brodarac (mentor)
• Committee member: Natalija Dolić (predsjednik povjerenstva)
• Committee member: Zdenka Zovko Brodarac (član povjerenstva)
• Committee member: Ivan Jandrlić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2019-09-12, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy

Abstract

Mehanička svojstva aluminijskih legura ovisna su o mikrostrukturnim parametrima poput
veličine i oblika zrna, udaljenosti između dendritnih grana, veličini i raspodjeli primarnih i
sekundarnih faza i uključaka. Kontrola tih parametara ostvaruje se obradom taline te
utjecajem na proces skrućivanja i hlađenja. Obrada taline provodi se s ciljem usitnjenja
primarnog zrna aluminija cijepljenjem, odnosno modifikacijom mehanizma rasta eutektika
(α-Al + β-Si).
U ovom je radu ispitana AlSi12 legura za proizvodnju gravitacijski lijevanih zateznih
stezaljki u tvrtki Dalekovod d.o.o. Cilj provedenog istraživanja bio je procijeniti utjecaj
tehnološke obrade taline i debljine stjenke na razvoj mikrostrukture i mehanička svojstva
AlSi12 legure gravitacijski lijevane u pješčani kalup i kokilu. Istraživanje je temeljeno na
hipotezi da se odgovarajućom tehnološkom obradom taline može poboljšati metalurška
kvaliteta taline te na taj način utjecati na razvoj i pojavu grešaka u mikrostrukturi.
Modifikacija taline dodatkom sredstva na bazi natrija, odnosno stroncija, osigurala je
izlučivanje eutektika (α-Al + β-Si) potpuno modificirane morfologije te smanjenje razlike u
mikrostrukturi i mehaničkim svojstvima.

Abstract (english)

Mechanical properties of aluminum alloys depend on microstructural parameters such as
grain size and shape, distance between dendritic arms, size and distribution of primary and
secondary phases and inclusions. These parameters are controlled by melt processing and the
influence on solidification and cooling process. The melt treatment is carried out by refining
of primary aluminum grain by inoculation or by modification of the eutectic (α-Al + β-Si)
growth mechanism.
This paper examines AlSi12 alloy for the production of gravity cast clamps in a company
Dalekovod d. o. o. The aim of this study was to evaluate the influence of technological
processing of melt and wall thickness on the development of microstructure and mechanical
properties of AlSi12 alloy using gravity casting in sand mold and permanent mold. The
research is based on the hypothesis that adequate technological processing of the melt can
improve the metallurgical quality of the melt and thus influence the development and
occurrence of defects in the microstructure. Modification of the melt with the addition of
sodium or strontiumbased agents provided complete modification of eutectic (α-Al + β-Si)
morphology and reduced the difference in microstructure and mechanical properties.

• Keywords: AlSi12 legura; cijepljenje; modifikacija; mikrostruktura; mehanička svojstva
• Keywords (english): AlSi12 alloy; inoculation; modification; microstructure; mechanical properties
• Language: croatian
• URN:NBN: urn:nbn:hr:115:898439
• 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: 2019-09-26 09:16:27