塑性变形产生的影响因素（The influence factors of plastic deformation）.docVIP

塑性变形产生的影响因素（The influence factors of plastic deformation） Influence factor of plastic deformation The plastic deformation of metals at room temperature has great influence on the microstructure and properties of metals. There are many kinds of phenomena such as work hardening, internal stress and anisotropy. Work hardening The plastic deformation leads to dislocation propagation, dislocation density increases, and plastic deformation mechanical principle of dislocation in different directions The movement of dislocations is hindered, resulting in metal working hardening. Work hardening can improve the hardness, strength and deformation resistance of metals, while reducing plasticity, so that the subsequent cold deformation difficult. internal stress The plastic deformation of metal distribution in the body is not uniform, so the external force is removed, the elastic recovery is not exactly the same, stress the balance among the body causes the metal parts, namely residual stress. The residual stress reduces the dimensional stability of the parts and increases the tendency of stress corrosion. Anisotropy When the metal is deformed in cold state, there is a slip band or twin band in the grain. The grains also stretch and twist in the direction of deformation. When the deformation is large (70% or greater) and along one direction, the atomic arrangement of grain orientation consistency, at the same time the existence of internal metal inclusions were elongated along the direction of deformation formation of fibrous tissue, the anisotropy of metal. The strength, plasticity and toughness in the direction of deformation are higher than those in the transverse direction. When the metal is deformed in hot state, the orientation of the grain will deviate from the deformation direction to a certain extent due to recrystallization, but the direction of the fiber formed by the elongation of the inclusions remains unchanged and the metal is still anisotropic. Recrystallization