Load partitioning in Zr-2.5%Nb during compression

A series of TOF neutron diffraction in-situ uniaxial compression tests have been carried out on textured Zr-2.5Nb. Test samples were prepared from the hot rolled plate with a moderate texture where the basal plane normal is mainly distributed between the transverse (TD) and plate normal (ND) directions. In a set of tests, load was applied along each of the three principle directions, and the evolution of the lattice strain was also measured in these directions. The intergranular strain was monitored by single peak fits while the interphase strain was obtained by Rietveld refinements. Results show that the load sharing changes between the α- and β-phases at various macroscopic applied loads. The β-phase yields first and then takes a smaller load increment for increasing macroscopic stress. The β-phase yields at a higher applied stress and the load is then transferred back to the β-phase. Load partitioning also occurs between differently oriented grain families in each phase. This load partitioning produces residual interphase and intergranular stresses in Zr-2.5Nb. The average residual phase stress is low in the β-phase, however, the intergranular stresses can be significant. (author)