Surface microstructure and properties of nodular cast iron rapidly solidified by laser surface melting+1

Reita Murakami, Ichihito Narita, Hirofumi Miyahara

Research output: Contribution to journalArticle

Abstract

Ferrite-matrix nodular cast iron has been modified by a laser surface melting process to develop its microstructure and to improve the surface hardness. A YAG laser beam was irradiated on a substrate and the microstructure of the melted layer was investigated as a function of the pulse energy at a constant specimen travel speed. The surface of the specimen is melted and then rapidly solidified up to a depth of 100 µm order. The melted depth increases with increasing pulse energy. In addition, the ferrite-phase matrix around the spheroidal graphite in cast iron preferentially melts because several alloying elements are segregated at the ferrite/graphite interface. The solidified layer consists of three distinctive parts: first, a martensite phase appears in the vicinity of the melted/unmelted substrate interface, then single-phase austenite crystallized on the martensite phase, and finally a ledeburite-austenite hybrid structure unidirectionally solidified from the substrate towards the surface. A cooling rate from 0.3 to 2.4

Original languageEnglish
Pages (from-to)1465-1470
Number of pages6
JournalMaterials Transactions
Volume59
Issue number9
DOIs
Publication statusPublished - Jan 1 2018

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All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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