Thermal microstress and microstrain develop in polycrystalline zinc powder particles due to anisotropic thermal expansion, as revealed by corresponding diffraction-line broadening. The extent and distribution of the microstrain will depend on the ratio between the powder particle size and the size of the constituting crystallites. Crystallites at the surface of the particles are mechanically less restricted than such in the inner region of the powder particles. Upon continuing a previously conducted, very successful temperature-dependent (between 300 K and 15 K) neutron powder-diffraction study on dedicatedly sieved coarse-particle zinc, we will now use smaller sized fractions of the corresponding original powder to study systematically the role of the surface effects but also of plastic deformation on the peak profiles.