PHYSICAL AND MECHANICAL, PROPERTIES OF COLUMBIUM AND COLUMBIUM-BASE ALLOYS

摘要

The need for structural materials for service at temperatures in excess of those attainable with present materials of construction has sparked interest in the refractory metals. Until about 1957, molybdenum -was considered the chief prospect for such use. However, because no satisfactory way of overcoming molybdenum's propensity to oxidize has been found, interest has turned to columbium as an alloy base.nColumbium is inherently a soft, ductile, readily fabricable material. Although its melting temperature is about 4380 F, pure columbium becomes too weak for structural use at temperatures above about 1200 F. Columbium is a very reactive metal, in that it dissolves large quantities of oxygen and probably nitrogen on exposure to atmospheres containing even small amounts of these elements at modest temperatures. The technology of columbium and its alloys is affected accordingly.