Determination of fracture toughness of boride layers grown on Co1.21Cr1.82Fe1.44Mn1.32Ni1.12Al0.08B0.01 high entropy alloy by nanoindentation
Ceramics International, vol.48, no.24, pp.36410-36424, 2022 (SCI-Expanded, Scopus)
- Publication Type: Article / Article
- Volume: 48 Issue: 24
- Publication Date: 2022
- Doi Number: 10.1016/j.ceramint.2022.08.201
- Journal Name: Ceramics International
- Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Communication Abstracts, INSPEC, Metadex, Civil Engineering Abstracts
- Page Numbers: pp.36410-36424
- Keywords: Boriding, Fracture toughness, High entropy alloys, Nanoindentation
- Hatay Mustafa Kemal University Affiliated: Yes
Abstract
Multiphase boride layers consisting of (CoFe)2B, (Fe0.4Mn0.6)B, Cr2Ni3B6 and (Cr0.4Mn0.6)B were formed on the surface of Co1.21Cr1.82Fe1.44Mn1.32Ni1.12Al0.08B0.01 high entropy alloy by powder-pack boronizing at 900 °C, 950 °C and 1000 °C for 4 h. The nanohardness (H), modulus of elasticity (E) and fracture toughness (KC) of the multiphase boride layers were determined based on the load–displacement (P-h) curves obtained in the nanoindentation tests. Three distinct regions were identified on the cross-sections of the produced layers: an outer layer consisting of MeB-type borides, an inner layer consisting of Me2B-type borides and the transition zone. The microstructural aspects of the layers were investigated using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. Detailed analysis of the influence of the chemical composition on hardness, elastic modulus and fracture toughness in the three regions indicated that the most critical factor influencing the mechanical properties was the presence of chromium, iron and cobalt borides in the microstructure. Especially the formation of chromium borides reduced the fracture toughness of the transition zone.