Abstract
This paper reports the results of a study of the effects of nitrogen on the intergranular segregation and fracture behaviour of molybdenum. Samples exhibiting a ‘bamboo-type’ grain structure were nitrogen doped to various levels. Most of the grain boundary orientation deviated by an angle Δθ (1-10°) from the precise coincident site lattice orientation.
The driving force for oxygen segregation was greater than that for nitrogen segregation at the temperatures 1873-2233 K. Increasing the bulk concentration of nitrogen enhanced the oxygen segregation, whilst having a less significant effect on the nitrogen segregation.
The fracture energy decreased with increasing segregation levels of oxygen and nitrogen. However, it was suggested that the fracture energy was not solely a function of the grain boundary segregation but also depended on the geometrical nature of the grain boundary.
