Preiskava nastajanja vročih razpok pri zlitinah Al-Zn

Dolinar, Gal (author), Tonn, Babette (mentor), Mrvar, Primož (co-mentor)

Vroče trganje je ena od napak, ki se pojavljajo med ulivanjem aluminijevih zlitin. Poznavanje mehanizmov vročega trganja je zelo pomembno, če želimo proizvajati kvalitetne izdelke iz aluminijevih zlitin. V zaključni nalogi so bili preiskovani mehanizmi vročega trganja v aluminijevih ulitkih. Poudarek je na problemu vročega trganja v AlZn9 zlitinah za uporabo v različnih vejah industrije, vključno z avtomobilsko in vesoljsko. Predstavljen je pregled preizkusov, ki so primerni za preiskovanje vročega pokanja. Določili smo zadnje temperaturno področje strjevanja (angl. Terminal Freezing Range, TFR), v katerem je napajanje že močno ovirano. Izračunano je bilo s pomočjo Scheil – Gulliverovega modela za vse štiri preiskovane zlitine; • AlZn9Mg2,3Cu2,3 • AlZn9Mg2,3Cu2,6 • AlZn9Mg2,6Cu2,3 • AlZn9Mg2,6Cu2,6 Enake zlitine so bile nato ulite v trajno kokilo, ki je bila oblikovana posebej za preiskave vročega pokanja. Ulitki so bili optično ocenjeni. Narejena je bila primerjava med napovedanim in izmerjenim TFR-om. Med eksperimenti smo kontrolirali nastanek vročih razpok. Z instrumentalno kokilo so bili izmerjeni sila, temperature in pomik med strjevanjem. Rezultati so predstavljeni na koncu tega dela. Na koncu so rezultati ovrednoteni in predstavljeni so predlogi za nadaljnje delo.

• Language: Slovenian
• Keywords: vroče trganje, aluminijeve zlitine, oblikovanje razpok v vročem, ulitek
• Work type: Bachelor thesis/paper
• Organization: NTF - Faculty of Natural Sciences and Engineering
• Year: 2017
• PID: 20.500.12556/RUL-92659
• Publication date in RUL: 24.06.2017

Secondary language

• Language: English
• Title: Investigation of the hot tearing formation in Al-Zn alloys

Abstract

Hot tearing is presented as one of defects, which occurs during casting of aluminium alloys. If we want to cast quality products from aluminium alloys is very important to know causes and mechanisms of hot tearing. In present work, mechanisms of hot tear formation in aluminium castings were studied. The main focus will be on the problem of hot cracking in AlZn9 alloys for applications in various industries, including automotive and aerospace. Overview of experiments, which are suitable for hot tearing investigations is introduced. Terminal freezing range (TFR) is calculated with use of Scheil – Gulliver model for all of the four investigated alloys; • AlZn9Mg2,3Cu2,3 • AlZn9Mg2,3Cu2,6 • AlZn9Mg2,6Cu2,3 • AlZn9Mg2,6Cu2,6 Same alloys were then cast in permanent mould, which was designed for investigation of hot tears. Castings were optically evaluated. Comparison of predicted TFR with TFR from measurements from the experiments was made. Formation of hot cracks was monitored during experiments with instrumented rod mould. Force, temperature and displacement were measured during casting. At the end, results are described and suggestions are presented.

• Keywords: hot tearing, aluminium alloys, hot tear formation, casting