Study On Stress-strain Field And Microstructure Of The Local Laser Treatment In Commercially Pure Zirconium

In this paper, ANSYS is adopted to simulate the distribution law of temperature field,stress field and strain field during the laser irradiation on the pure zirconium. On this basis,we choose the appropriate parameters of the laser irradiation experiments. And theevolution of microstructure during the laser irradiation process is investigated by usinganalysis means, such as optical microscopy, X-ray diffraction, transmission electronmicroscopy(TEM) and electron back scattering diffraction(EBSD). The results of ANSYSsimulation show that it can produce the complex stress and strain fields during the laserirradiation on the pure zirconium. And the calculations of Von Mises equivalent stress andstrain indicate that it can make the pure zirconium produce plastic deformation bycontrolling the parameters of the laser irradiation experiments, which provides theoreticalbasis of setting process parameters of the laser treatment.The laser irradiation can obviously increase the hardness of pure zirconium. Theresults of EBSD indicate that sub-boundaries increase obviously and the microstructurechanges apparently after laser irradiation. When the temperature of laser irradiation iscertain(300℃), the number of sub-boundaries increase with the increase of theirradiation times. And when the irradiation times of loop irradiation is certain(300cycle),the number of sub-boundaries decrease sharply with the temperature of laser irradiationincreasing from700℃to800℃, which may be the result of recrystallization. Theanalysis of transmission electron microscopy (TEM) shows that the pure zirconium afterthe laser irradiation produces a lot of dislocations, stacking faults and a large number ofsubgrains. In addition, these dislocations, stacking faults and subgrains is the mian causeto increase hardness. The analysis of XRD indicates that the crystallite sizes in purezirconium reduce obviously with increasing the irradiation times after the laserirradiation at700℃.