SIGNIFICANT EFFECT OF CARBON CONTENT IN THE LOW-TEMPERATURE FRACTURE-BEHAVIOR OF MOLYBDENUM

Low-temperature strength and ductility of powder-metallurgy molybdenum and electron-beam-melted molybdenum and its alloys which have been recrystallized or electron-beam-welded is examined from the viewpoint of carbon content and microstructures. Critical stress and critical temperature primarily depended on the carbon content. A small amount of carbon substantially enhanced the critical stress, and consequently lowered the critical temperature. The effects of microstructural changes such as grain size and precipitates size and distribution as a result of alloying and/or welding on the above results were secondary. © 1990, The Japan Institute of Metals. All rights reserved.