On the transgranular type of tempered martensite embrittlement

• Published in: Scripta metallurgica et materialia Vol. 30; no. 9; pp. 1111 - 1115
• Main Authors: Lee, Kon Bae, Yoon, Sang Hoon, Kwon, Hoon
• Format: Journal Article
• Language: English
• Published: Seoul Elsevier B.V 01.05.1994; Oxford Pergamon Press; New York, NY
• Subjects: ALLOYS; Applied sciences; CARBIDES; CARBON COMPOUNDS; Cross-disciplinary physics: materials science; rheology; DATA; ELEMENTS; EMBRITTLEMENT; Exact sciences and technology; EXPERIMENTAL DATA; Fatigue, corrosion fatigue, embrittlement, cracking, fracture and failure; Fatigue, embrittlement, and fracture; FRACTURE PROPERTIES; INFORMATION; IRON ALLOYS; IRON BASE ALLOYS; MARTENSITIC STEELS; MATERIALS SCIENCE; MECHANICAL PROPERTIES; METALLURGICAL EFFECTS; METALS; Metals. Metallurgy; MOLYBDENUM; NUMERICAL DATA; Physics; STEELS; TRANSITION ELEMENTS 360103 > Metals & Alloys > Mechanical Properties; Treatment of materials and its effects on microstructure and properties; TUNGSTEN; Ruptures; Charpy impact test; Tempering; Martensitic steels; Impact strength; Embrittlement; Hardness; Experimental study; Temper brittleness; Microstructure; Fractography; Heat treatments
• ISSN: 0956-716X
• DOI: 10.1016/0956-716X(94)90323-9

A phenomenon where toughness and strength of martensitic alloy steels are reduced, when tempered at 250-400 deg C, is called tempered martensite embrittlement (TME). There are two types of TME based upon fracture mode. Transgranular type of TME has been analyzed for its impact toughness, fracture behavior and microstructures on isothermal tempering. Molybdenum and MoW steels were used for experimentation because they may decrease the intrinsic toughness and produce easy transgranular brittle fracture. Impact testing was carried out and transmission electron microscope was used for studying the specimens. Results obtained were discussed. Molybdenum and MoW steels represented the quasi-cleavage fracture. The formation of coarse carbides at martensite lath boundaries results in TME which makes easy transgranular brittle fracture in the matrix of low intrinsic toughness with the tungsten and/or Mo additions.