Effect Of Hot Compression And Cold Compression Annealing On Microstructure And Properties Of 5B70 Alloy Sheet

The properties of 5B70-H112 alloy cannot be strengthened by heat treatment,but can be further improved by plastic deformation.This will produce stress and defects,in order to avoid this phenomenon in the actual production of alloy hot deformation or cold deformation annealing treatment.In these two processing technologies,the deformation temperature and annealing temperature will soften the alloy.In order to retain more deformation structure and further improve the properties of the alloy,the 5B70-H112 alloy plate was subjected to hot pressing and cold pressing annealing under different conditions.The performance of the sample was tested by electronic uniaxial tensile test（UST）and Vickers hardness（HV）,and the microstructure was characterized by electron backscatter diffraction（EBSD）,scanning electron microscopy（SEM）and transmission electron microscopy（TEM）.Microstructure and properties of hot compression specimens and dynamic recrystallization and microstructure and properties of cold pressed annealed specimens and static recrystallization were studied.The relationship between deformation conditions,microstructure,dislocation density,softening behavior and properties was discussed.The results are as follows:In the first part,hot pressing deformation of 5B70 alloy sheet under different conditions was carried out.The strength and hardness of the alloy increase with the increase of deformation amount and the decrease of deformation temperature.The tensile strength and yield strength of the alloy are 481MPa and 391MPa respectively under hot pressing at 60%-200℃,and the hardness reaches 131HV.The fiber crystal size decreases with the increase of deformation,and gradually breaks into fine grains.The dislocation density and the number of subgrains are also increasing.At the same time,the subgrain size increases with the increase of variable temperature.At low temperature and small deformation,the alloy is mainly dynamic recovery mechanism,and at high temperature and large deformation,the alloy is mainly continuous dynamic recrystallization.The increase of deformation temperature leads to the increase of Al₃（Sc,Zr）particle size and spacing,which weakens the pinning effect.The strong Brass{011}<211>orientation was generated after hot pressing deformation,and the Brass texture began to shift to the Cube{001}<100>texture with the increase of temperature.In the second part,the alloy plates were subjected to cold pressing annealing under different conditions.The strength and hardness of the alloy increase with the increase of cold pressure as a whole,and decrease with the increase of annealing temperature,and the softening effect is more obvious with the increase of cold pressure.Under cold pressure annealing at 60%-200℃,the strength and hardness reached the highest,with tensile strength and yield strength of 466MPa and 384MPa,respectively,and Vickers hardness of 131HV.The alloy is mainly dynamic recovery under small deformation.When the deformation exceeds 40%,the increase of annealing temperature increases the subgrain size and reduces the dislocation distribution.After annealing at 450℃,recrystallized grains distributed along the rolling direction are generated,and there are many recrystallization mechanisms.Under small deformation,Brass texture begins to transform to Goss{011}texture with the increase of annealing temperature.Recrystallization textures such as Goss and Cube textures appeared after high-temperature annealing of 40%and 60%cold-pressed samples.By comparison,it is found that there are more deformation structures in the hot-pressed sample,so that its strength and hardness are generally higher than those of the cold-pressed annealing sample.The optimum hot pressing process of the alloy is 60%+300℃,which can take into account both properties and workability.The tensile strength and yield strength of the alloy are 457MPa and 377 MPa,respectively.The elongation is 12.4%and the hardness is 128HV.The alloy was mainly dynamic recovery without recrystallization.The dislocation density was 5.32×10¹⁵/m²,which was 51%higher than that of the original sample,and a large number of deformation structures such as substructures were formed.At the same time,the Al3（Sc,Zr）particles were not coarsened and uniformly distributed,and there were strong substructure strengthening and second-phase particle strengthening.219 Figures,7 Tables,82 References...