Analiza sastava, mikrostrukture i svojstava navara od aluminijske bronce

master's thesis

• Title (english): Analysis of the composition, microstructure, and properties of the aluminium bronze overlay
• Author: Frano Karačić
• Mentor: Vera Rede (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-12-15, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U radu je provedena analiza kemijskog sastava i mikrostrukture te ispitivanje mehaničkih
svojstava navara od aluminijske bronce oznake CuAl8Ni2Fe2Mn2 na osnovnom materijalu
oznake CuAl10FeNi5.
U teorijskom dijelu rada opisan je bakar te njegove legure, a posebna pozornost je posvećena
broncama i njihovoj primjeni.
U eksperimentalnom djelu rada utvrđen je kemijski sastav osnovnog materijala i metala
navara koji odgovara propisanim kemijskim sastavima.
U mikrostrukturi osnovnog materijala vidljiva je α-faza i eutektoid te precipitati κ-faze. Linija
staljivanja je jasno izražena, dok je područje utjecaja topline relativno usko bez nepravilnosti.
Metal navara ima tipičnu ljevačku dendritnu usmjerenu mikrostrukturu bez uočenih
nepravilnosti.
Najviše vrijednosti tvrdoće izmjerene su u zoni utjecaja topline, 216 HV0,2 i 220 HV10.
Tvrdoća osnovnog materijala iznosila je 196 HV0,2 i 191 HV10, a slična vrijednost je
izmjerena i u prvom navarenom sloju, dok se tvrdoća u drugom i trećem navarenom sloju
postupno smanjuje.
Također je utvrđeno da osnovni materijal i metal navara nemaju veliku sposobnost savijanja
zbog pojave puknuća pri malom kutu savijanja.
Nakon provedene analize rezultata utvrđena je zadovoljavajuća kvaliteta navara pod uvjetom
da područje navara tijekom eksploatacije ne bude savojno opterećeno.

Abstract (english)

In this thesis, an analysis of the chemical composition and microstructure was carried out, in
addition, the mechanical properties of the overlay of aluminum bronze mark
CuAl8Ni2Fe2Mn2 on the base material CuAl10FeNi5 were tested.
In the theoretical part of the thesis, copper and its alloys are described, and special attention is
paid to bronzes and their applications.
In the experimental part of the thesis, the chemical composition of the base material and
overlay metal was examined and proved to match the prescribed chemical compositions.
In the microstructure of the base material α-phase, eutectoid and κ-phase precipitates are
visible. The melting line is clearly defined, while the heat-affected zone is relatively narrow
without irregularities. Overlay metal has a typical foundry dendritic-oriented microstructure
without observed irregularities.
The highest hardness values were measured in the heat-affected zone, 216 HV0.2 and 220
HV10. The hardness of the base material was 196 HV0.2 and 191 HV10, and a similar value
was measured in the first overlay layer, while the hardness in the second and third overlay
layers gradually decreases.
It was also determined that the base material and overlay metal do not have great bending
properties due to the appearance of cracks at small bending angle.
After the analysis of the results, the satisfactory quality of the overlay was determined,
provided that the area of the overlay is not subjected to bending stress during exploitation.

• Keywords: aluminijska bronca; navar; mikrostruktura; tvrdoća; savijanje
• Keywords (english): aluminium bronze; overlay; microstructure; hardness; bend strenght
• Language: croatian
• URN:NBN: urn:nbn:hr:235:358634
• 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: 2022-12-05 06:01:34