Preparation And Micromechanical Behavior Of Mg Matrix Composites Reinforced By Ti Particles

Magnesium alloy has many advantages and characteristics such as low density,high specific strength and stiffness,excellent shock absorption and abundant reserves,which make it become a research hotspot in the field of energy saving and lightweight materials in recent years.However,the shortcomings of magnesium alloy,such as low toughness and poor thermal stability,greatly limit its wide application.Magnesium matrix composites based on magnesium alloy can not only retain the advantages of magnesium alloy,but also make up for its low hardness by adding other materials,which has become one of the materials attracting much attention.At present,the research on magnesium matrix composites reinforced by metal particles is relatively rare.Therefore,whether by adding some metal particles into the magnesium alloy,the overall strength of the composite can be improved,but also reduce the loss of plasticity,so as to obtain a magnesium matrix composite with better mechanical properties is the significance of this research.In this paper,AZ61 magnesium alloy powder was used as matrix phase and Ti particles were used as reinforcement phase.The two powders were refined and mixed by mechanical ball milling.It was found that after 20 h high energy ball milling,both pure AZ61 alloy powder and Ti/AZ61 composite metal powder with different Ti contents were processed.The size of the powder particles is obviously refined,and the deformation of the particles is more serious to become irregular polyribbed particles,and several particles are compacted and stuck to become large particles after extrusion and collision.Ti/AZ61 composites were prepared by means of spark plasma sintering(SPS).The microstructure and selected components of sintered billet were observed and analyzed by means of optical microscope and scanning electron microscope,and the density and compressive mechanical properties of composite materials were tested.The mechanical properties parameters of composite materials were obtained to prepare for the subsequent microscopic mechanical model simulation.By room temperature compression test,it is found that the addition of enhanced particle Ti can significantly improve the mechanical properties of composites,and the yield strength,compressive strength and fracture strain of 0.5wt.%Ti/AZ61 composites intersecting pure AZ61 sintered billet material are increased by 41.93%,94.60% and98.89%,respectively.In addition,it is revealed that the fracture mechanism of composites at room temperature is mainly brittle fracture mechanism.Finally,the representative volume element(RVE),a mesomechanical model of Ti/AZ61 composites,was obtained through simulated modeling,and the corresponding compression simulation analysis of the model was carried out with the finite element analysis software Abaqus.The compressive fracture mechanism of Ti/AZ61 composites was revealed by simulating the compression deformation process of RVE model.Ti particles as reinforcement phase played a bearing role,and the aggregation or uneven distribution of particles in the matrix would have a negative effect on the fracture of the matrix.