Utjecaj hladne i tople plastične deformacije na korozijsku postojanost aluminijskih slitina

undergraduate thesis

• Title (english): Effect of cold and hot plastic deformation on corrosion resistance of aluminum alloys
• Author: Karla Krolo
• Mentor: Zdenka Keran (mentor)
• Granter: University of Zagreb; Faculty of Mechanical Engineering and Naval Architecture; Zagreb
• Defense date and country: 2022-09-28, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Mechanical Engineering

Abstract

U ovom radu opisana su opća svojstva aluminija i njegovih legura te značajan utjecaj
na mehanička, fizikalna i kemijska svojstva metalnih materijala, točnije aluminija. Jedan od
važnijih utjecaja nakon plastične deformacije odnosi se na promjene postojanosti metalnih
materijala.
Aluminij u odnosu na druge metale ima puno prednosti poput male mase, velike
otpornosti na koroziju, mogućnosti recikliranja, jednostavnost obrade, itd. Poseban naglasak je
stavljen na pozitivan, ali i negativan utjecaj plastične deformacije na korozijsku postojanost,
koja naravno ovisi o načinu i temperaturi procesa te o vrsti materijala, odnosno njegovoj
čvrstoći. Niska čvrstoća aluminija poboljšava se legiranjem. Plastična deformacija definirana
je kao kretanje dislokacija kroz kristalnu rešetku materijala koja nastaje zbog naprezanja.
Povećanjem stupanja deformacije, veća je i gustoća dislokacija u strukturi materijala. Veća je
tvrdoća, ali je manja otpornost na koroziju.
Povećanjem debljine površinskoga oksidnog sloja elektrokemijskim
putem (eloksiranjem), povećava se otpornost aluminija prema koroziji. Tanak sloj koji nastaje,
oksidni sloj, je porozan, može se obojiti i prevući organskim bojama. Boja trajno ostaje u
oksidnome sloju jer se pore se zatvaraju na povišenoj temperaturi. Na korozijsku postojanost
aluminijskih legura utječe u stupanj deformacije materijala. Ovaj utjecaj veći je kod nekih
legura sa magnezijem (serija 5000) i silicijem (serija 6000) te se postižu bolja mehanička
svojstva u slučaju toplog plastičnog oblikovanja. Primjena aluminijskih legura ograničena je
pri povišenim temperaturama zbog niske temperature tališta aluminija (660 °C). Uporaba
njihovih legura dozvoljena je do temperature od 150 °C do najviše 200 °C.

Abstract (english)

This paper describes the general properties of aluminum and its alloys, significant
influence on the mechanical, physical and chemical properties of metal materials, specifically
aluminum. One of the morst important influences after plastic deformation refers to changes in
the durability of metallic materials.
Compared to other metals, aluminum has many advantages, such as low weight, high resistance
to corrosion, recyclability, ease of processing, etc. Special emphasis is placed on the positive
and negative impact of plastic deformation on corrosion resistance, which of course, depends
on the method and temperature process and on the type of material, i.e. its strength. The low
strength of aluminum is improved by alloying. Plastic deformation is defined as the movement
of dislocations through the crystal lattice of the material that occurs due to strain. By increasing
the rate of deformation, the density of dislocations in the material structure also increases. It
has higher solidity, but lower resistance to corrosion.
Aluminum's resistance to corrosion increases by increasing the thickness of the surface
oxide layer by electrochemical means (anodization). The resulting thin layer, the oxide layer,
is porous and can be painted and coated with organic dyes. The color remains permanently in
the oxide layer because the pores close at elevated temperatures. The corrosion resistance of
aluminum alloys is affected by the degree of deformation of the material. This influence is
greater in some alloys with magnesium (series 5000) and silicon (series 6000), and better
mechanical properties are achieved in the case of hot plastic forming. The use of aluminum
alloys is limited at elevated temperatures due to the low melting point of aluminum (660 °C).
Their use is permitted up to a temperature of 150 °C to a maximum of 200 °C

• Keywords: aluminij; aluminijske legure; topla i hladna deformacija
• Keywords (english): aluminum; aluminum alloys; hot and cold deformation
• Language: croatian
• URN:NBN: urn:nbn:hr:235:465317
• Study programme: Title: Mechanical Engineering; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva (sveučilišni/a prvostupnik/ prvostupnica (baccalaureus/baccalaurea) inženjer/inženjerka strojarstva)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2022-09-27 13:39:10