Masao Hayakawa

Atomic force microscopy of induction- and furnace-heating-tempered prestressed steels with different delayed fracture properties

Abstract Quantitative microstructure analyses by atomic force microscope and delayed fracture tests were performed for two types of prestressed steel with a tensile strength of 1470 MPa; an induction-heated-tempered specimen, and a furnace-heated-tempered specimen. Size distributions of cementite particles were measured to characterize the relationship between microstructures and delayed fracture properties.

Nanoscopic measurement of local plastic deformation for a tempered martensitic steel by atomic force microscopy

Abstract A technique for analyzing the local plastic deformation at the surface of a tensile test specimen was developed by atomic force microscopy (AFM). When tensile plastic strains of 2×10−3, 4×10−3 and 6×10−3 were applied to the specimen of a tempered martensitic steel, surface steps with 5–39 nm were observed in locally deformed blocks near prior austenite (γ) grain boundaries.