Lasersko pretaljevanje aluminijeve zlitine 7075

Trifković, Anže (author), Šturm, Roman (mentor)

V zaključni nalogi smo s trdninskim, pulznim Nd:YAG laserjem lasersko pretaljevali toplotno obdelano aluminijevo zlitino 7075-T6 in obravnavali vpliv velikosti pege laserskega žarka in moči laserja na globino penetracije in spremembo trdote pretaljene površine v primerjavi z osnovnim materialom. Izmerili smo tudi nastale zaostale napetosti v vzorcu. Dokazali smo, da gostota energije laserskega žarka nima bistvenega vpliva na doseženo trdoto pretaljene površine. Mikrostruktura se je spremenila v finozrnato, trdota pa se je glede na dobavljeno kvaliteto Al 7075-T6 zmanjšala. Če bi uporabili zlitino Al 7075-T0, ki ni predhodno toplotno obdelana s staranjem, bi se trdota povečala. V posameznih sledeh laserskega žarka so zaostale napetosti opazno večje, kot pa v večji pretaljeni površini, ki smo jo dobili s prekrivanjem sledi.

• Language: Slovenian
• Keywords: lasersko pretaljevanje, aluminijeve zlitine, zaostale napetosti, trdota, mikrostruktura
• Work type: Final paper
• Typology: 2.11 - Undergraduate Thesis
• Organization: FS - Faculty of Mechanical Engineering
• Place of publishing: Ljubljana
• Publisher: [A. Trifković]
• Year: 2019
• Number of pages: XIV, 30 f.
• PID: 20.500.12556/RUL-110179
• UDC: 621.785.54:669.715(043.2)
• COBISS.SI-ID: 16952347
• Publication date in RUL: 12.09.2019

Secondary language

• Language: English
• Title: Laser melting of aluminium alloy 7075

Abstract

In the final thesis, we used a solid-state, pulsed Nd:YAG laser to melt heat-treated aluminum alloy 7075-T6 and discussed the influence of the laser beam spot size and the laser's power on the penetration depth and change in the hardness of the treated surface compared to the base material. Residual stresses in the sample were also measured. We have demonstrated that the laser beam energy density does not have a significant effect on the attained hardness of the melted surface. The microstructure turned into fine-grained, and the hardness decreased in terms of the delivered Al 7075-T6 quality. If an Al 7075-T0 alloy, not pre-treated with aging, had been used, the hardness would have increased. In the individual traces of the laser beam, the residual stresses are noticeably larger than in the larger melted surface obtained by overlaying the traces.

• Keywords: laser melting, aluminium alloys, residual stress, hardness, microstructure