Evaluation of Cleavage Fracture Behavior of C14 Fe2W Laves Phase by First-principles Calculations and Crystal Orientation Analysis

• Published in: ISIJ International 2022/10/15, Vol.62(10), pp.2118-2125
• Main Authors: Yamasaki, Shigeto, Morikawa, Tatsuya, Tanaka, Masaki, Watanabe, Yasuaki, Yamashita, Mitsuo, Izumi, Sakae
• Format: Article
• Language: English
• Subjects: cleavage fracture plane; ductile-to-brittle transition; elastic constant; electron backscattered diffraction; ferritic heat-resistant steel; first-principles calculation; fracture toughness; Laves phase; surface energy
• ISSN: 0915-1559; 1347-5460
• DOI: 10.2355/isijinternational.ISIJINT-2022-122

In this study, the cleavage fracture of the C14 Fe2W Laves phase was investigated by first-principles calculations and crystal orientation analysis using scanning electron microscopy. Trace analysis of the orientations of cleavage planes revealed that cleavage fracture occurred in five types of crystal planes: (0001), {1 1 00}, {11 2 0}, {1 1 01}, and {11 2 2}. Among these fractures, the fracture at (0001) is the most preferable. From, the first-principle calculations of the surface energy for fracture, Young’s modulus, and Poisson’s ratio, the minimum fracture toughness value of 1.62 MPa·m1/2 was obtained at (0001). The tendency of the calculated fracture toughness to become larger with high indexed planes is almost the same as the frequency of the types of cleavage planes in the trace analysis. It was concluded that the fracture toughness of the C14 Fe2W Laves phase is controlled by the surface energy for fracture and Young’s modulus.