3D Residual Strain in DKDP Crystals by Neutron Diffraction

Neutron diffraction technique is applied to study the three‐dimensional (3D) residual strains in K(H 1− x D x ) 2 PO 4 (DKDP) crystals with various deuterium contents (0 ≤ x ≤ 0.99). It is found that the residual strains in the crystalline coordinate are at the magnitude of 10 −3 to 10 −4 . The results show that the level of the macro‐strain in the crystal bulk is independent of the deuteration level. However, when the deuteration level is below 50%, the average of micro‐strain increases first with the increasing of deuteration level, then decreases when the deuteration level is in excess of 50%. According to the residual strains, the internal stresses are calculated through σ ij = C ijkl ε kl . Finally, the potential sources of the stresses in crystals are discussed and analyzed.