Energy density effect of laser alloyed TiB$_2$/TiC/Al composite coatings on LMZ/HAZ, mechanical and corrosion properties

Ravnikar, Dunja (author), Trdan, Uroš (author), Nagode, Aleš (author), Šturm, Roman (author)

In the present work, TiC/TiB$_2$/Al composite coatings were synthesized onto a precipitation hardened AlSi1MgMn alloy by laser surface alloying (LSA), using 13.3 J/mm$^2$ and 20 J/mm$^2$ laser energy densities. Microstructure evaluation, microhardness, wear and corrosion performance were investigated and compared with the untreated/substrate Al alloy sample. The results confirmed sound, compact, crackles composite coating of low porosity, with a proper surface/substrate interface. Microstructural analyses revealed the formation of extremely fine nano-precipitates, ranging from of 50–250 nm in the laser melted (LMZ) and large precipitates, accompanied with grain coarsening in the heat-affected zone (HAZ), due to the substrate overheating during the LSA process. Nonetheless, both coatings achieved higher microhardness, with almost 7-times higher wear resistance than the untreated sample as a consequence of high fraction volume of hard, wear resistant TiB$_2$ and TiC phases inside the composite coatings. Further, cyclic polarization results in 0.5 M NaCl aqueous solution confirmed general improvement of corrosion resistance after LSA processed samples, with reduced corrosion current by more than a factor of 9, enhanced passivation/repassivation ability and complete prohibition of crystallographic pitting, which was detected with the untreated Al alloy.

• Language: English
• Keywords: laser surface alloying (LSA), ceramic coatings on Al alloy, microstructure, laser melted/heat affected zone (LMZ/HAZ), microhardness, wear, corrosion
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: FS - Faculty of Mechanical Engineering; NTF - Faculty of Natural Sciences and Engineering
• Publication status: Published
• Publication version: Version of Record
• Year: 2020
• Number of pages: 19 str.
• Numbering: Vol. 10, iss. 3, art. 411
• PID: 20.500.12556/RUL-127266
• UDC: 620.1/.2:621.7+621.9(045)
• ISSN on article: 2075-4701
• DOI: 10.3390/met10030411
• COBISS.SI-ID: 17102363
• Publication date in RUL: 01.06.2021

Record is a part of a journal

• Title: Metals
• Shortened title: Metals
• Publisher: MDPI AG
• ISSN: 2075-4701
• COBISS.SI-ID: 15976214

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 23.03.2020

Secondary language

• Language: Slovenian
• Keywords: lasersko legiranje površine, keramične prevleke, aluminijeve zlitine, mikrostruktura, mikrotrdota, obraba, korozija

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P2-0270
• Name: Proizvodni sistemi, laserske tehnologije in spajanje materialov