The effect of nitrogen and oxygen on the mechanical properties of molybdenum

An investigation has been made of the effects of nitrogen and oxygen in solid solution on the mechanical properties of molybdenum single crystals. This is believed to be the first investigation of its type, involving the controlled addition of interstitfal solutes to a Group Vla metal. The establishment of a standard route for the preparation of molybdenum single crystals of well characterised purity has been undertaken as a necessary preliminary to the investigation of interstitially doped material. High purity molybdenum with a resistance ratio >5,000 and a total interstitial content < 10 at~ppm has been prepared by the successive zone-melting,decarburisation and high vacuum annealin;_" of commercial purity material. Resistance ratio measurements and chemical analysis have been used to define the purification mechanisms which operate durine; these treatments. A high speed quenching technique has been developed for doping molybdenum mechanical test specimens with nitrogen and oxygen., Compression specimens may be prepared with only small concentrations of interstitials in solid solution 0 at.ppm) but comparatively large concentrations (>100 at.ppm) may be quenched into solution in wire tension specimens., The nitrogen doped molybdenum is more thoroughly characterised than the oxygen doped molybdenum. [Abstract continued in thesis]