Release Time:2019-03-12  Hits:

Indexed by: Journal Article

Date of Publication: 2017-07-15

Journal: NUCLEAR INSTRUMENTS & METHODS IN PHYSICS RESEARCH SECTION B-BEAM INTERACTIONS WITH MATERIALS AND ATOMS

Included Journals: Scopus、EI、SCIE

Volume: 403

Page Number: 45-50

ISSN: 0168-583X

Key Words: High current pulsed electron beam; 40CrNiMo7 steel; Surface nanocrystallization; Microstructure; Microhardness

Abstract: In this paper, surface modification of 40CrNiMo7 steel was investigated with high current pulsed electron beam (HCPEB) treatment. The scanning electron microscope (SEM), electron back-scattered diffraction (EBSD), electron probe micro analysis (EPMA), transmission electron microscopy (TEM) and X-ray diffraction (XRD) results show that a composite microstructure of mainly refined austenite and a little marten site was produced in the surface modified layer of depth similar to 7 mu m. The average size of small cells on modified surface was decreased to similar to 120 nm after 25 HCPEB pulses. XRD analysis indicates a preferred orientation of austenite (220) crystal plane, and TEM results show the broken and dissolved cementite in the surface modified layer. After HCPEB treatment, all the samples exhibited a remarkable improvement in surface microhardness measurement, up to similar to 1000 HK for 15 HCPEB pulses, as tripled of the initial 40CrNiMo7 steel. (C) 2017 Elsevier B.V. All rights reserved.