Utjecaj brzine razvlačenja na pojavu Portevin-Le Chatelier efekta kod AlMg legure

master's thesis

• Title (english): Influence of the stretching rate on the appearance of the Portevin-Le Chatelier effect in the AlMg alloy
• Author: Milica Vučenović
• Mentor: Ivan Jandrlić (mentor)
• Mentor: Lorena Mrkobrada (pomoć pri izradi, neposredni voditelj)
• Committee member: Ljerka Slokar Benić (predsjednik povjerenstva)
• Committee member: Ivan Jandrlić (član povjerenstva)
• Committee member: Tin Brlić (član povjerenstva)
• Granter: University of Zagreb; Faculty of Metallurgy; Sisak
• Defense date and country: 2023-02-17, Croatia
• Scientific / art field, discipline and subdiscipline: TECHNICAL SCIENCES; Metallurgy

Abstract

Aluminij i legure na bazi aluminija u današnje vrijeme su neizostavni materijali o kojima ovisi industrija na globalnom nivou. Određene aluminijske legure, poput AlMg legura pokazuju nehomogenu, lokaliziranu deformaciju pri određenim temperaturama i brzinama deformacije poznatu kao Portevin–Le Chatelier (PLC) efekt. Portevin–Le Chatelier efekt pridonosi smanjenju duktilnosti materijala i pojavi grešaka na površini materijala što je naravno nepoželjno i predstavlja nerješiv problem, stoga se sve veća pažnja obraća na proučavanje pojave PLC efekta kako bi se navedene posljedice koje PLC efekt ostavlja minimizirale ili u potpunosti uklonile. Kod proučavanja utjecaja brzine razvlačenja na pojavu Portevin–Le Chatelier efekta kod AlMg4,5 legure u ovom diplomskom radu korištene su metode digitalne korelacije slike i infracrvene termografije paralelno sa statičkim vlačnim ispitivanjem primjenom konstantnih brzina razvlačenja 10 mm/min, 20 mm/min i 50 mm/min te konstantnim porastom naprezanja od 5 MPa/s i 10 MPa/s. Metodama digitalne korelacije slike i termografije je ustanovljeno kako do pojave PLC efekta dolazi pri svim primijenjenim brzinama razvlačenja i porastima naprezanja te kako se PLC linije formiraju kroz cijeli period plastične deformacije sve do loma uzorka. Također, kako je i za očekivati, ustanovljeno je kako s porastom brzine razvlačenja dolazi i do porasta brzine deformacije.

Abstract (english)

Aluminum and aluminum based alloys are nowdays irreplaceable materials on which industry worldwide depends. Certain aluminum alloys, such as AlMg alloys exhibit inhomogeneous, localized deformation at certain temperatures and strain rates known as the Portevin-Le Chatelier (PLC) effect. The Portevin-Le Chatelier effect contributes to the reduction of the materials ductility and the appearance of defects on the surface of material, which is obviously undesirable and represents an unsolvable problem. Therefore, more attention is paid to the study of the occurrence of the PLC effect, in order to minimize or completely eliminate the above consequences of the PLC effect. In this thesis, digital image correlation and infrared thermography methods were used simultaneously with static tensile testing in the study of the influence of stretching rate on the occurrence of the Portevin-Le Chatelier effect in AlMg alloy. The static tensile test was performed with constant stretching rates of 10 mm/min, 20 mm/min and 50 mm/min and with constant stress increase of 5 MPa/s and 10 MPa/s. Using the digital image correlation and infrared thermography methods it was found that the PLC lines formed throughout the entire period of plastic deformation until the specimen fractured. Also, as expected, it was found that as the stretching rate increased, the deformation rate also increased.

• Keywords: Aluminij; AlMg legure; Portevin-Le Chatelier efekt; brzina razvlačenja; statičko vlačno ispitivanje; digitalna korelacija slike; termografija
• Keywords (english): Aluminum; AlMg alloys; Portevin-Le Chatelier effect; stretching rate; tensile test; Digital Image Correlation; infrared thermography
• Language: croatian
• URN:NBN: urn:nbn:hr:115:608927
• 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: 2023-01-20 08:55:30