The Structure Evolvement And Mechanical Properties Study Of AM60B Alloy Under High Pressure

Magnesium alloy becomes an important novel structure material for its advantages such as low density, high specific strength and specific stiffness. However, the application of magnesium is limited by its low plasticity and corrosion resistance.The purpose of this work was to study the influence of microstructures and mechanical properties of AM60B alloy under high pressure. The heat-treatment muffle and cubic anvil high pressure apparatus was used to produce high temperature and pressure, and change the pressure and temperature simultaneously, the AM60B alloy was treated by taking solution and aging treatment of different processes, the effect of pressure on the microstructures and properties of the alloys were studied by analyzing the microstructures and properties of the alloys under different treatments.The microstructure and phases of AM60B alloys treated by different processes under high pressure were analyzed by optical micrograph and X-ray diffraction; the microstucture and substructure of AM60B alloys were observed by transmission electron microscope; the micro-hardness of the alloys were measured by the micro-hardness tester; the mechanical properties of the alloys were tested by Gleeble thermal-mechanical simulation tests.It was shown that pressure influenced the solution course of as-cast AM60B alloys, pressure promote the solution ofβ-Mg17Al12 phase when solution time reaches 30 minutes; pressure restrained the solution ofβ-Mg17Al12 phase when solution time reaches 60 minutes.After the high pressure solution state AM60B alloys treated by common pressure aging treatment, the average grain size decreased by 90%. The maximum of compressive strength is 285.90 MPa when solution pressure is 4 GPa. But the minimum of plastic strain is 14.8% when solution pressure is 4 GPa.After the common pressure solution state AM60B alloys treated by aging treatment of different pressures, pressure promote the separating out ofβ-Mg17Al12 phase, The maximum of compressive strength is 284.96 MPa when the alloys treated under solution of 400℃temperature and aging treatment of 3 GPa pressure, but the minimum of plastic strain is 14.1% when the aging treatment pressure is 3 GPa.Comprehensive comparing to the microstructure and compressive mechanical properties experimental results, the microstructure of AM60B alloy treated under solution of high pressure and common pressure aging treatment is better, and the alloy has the best mechanical properties treated under solution of 5 Gpa pressure and common pressure aging treatment, compared to common pressure solution and aging treatment, its compressive strength increased by 15.8%, the maximum of plastic strain increased by 2.7%.