Research On Explosive Compaction And Numerical Simulation Of Particle Reinforced Copper Matrix Composites

Particle reinforced copper matrix composites have not only excellent electric conductivity and heat conductivity but also high strength and hardness, well abrasion resistance and heat resistance, that have been used as electric resistance welding electrode, oxygen lance nozzle, IC lead frame, vacuum contact, etc. Existing preparation technology of particle reinforced copper matrix composites is very complex and costs very much, which lead to the materials' price is so high that application is limited.In this paper, a new preparation technology is proposed, that with simple equipment and low cost. By the new preparation technology, high-quality and low-price particle reinforced copper matrix composites can be obtained. The new preparation technology includes three basic steps: 1) Preparing uniformly mixed powders by mechanical alloy method. 2) Sintering the advance compacted powders in hydrogen atmosphere. 3) Preparing bulk materials by direct explosive compaction method. Thereinto, explosive compaction is the most important process among all the preparation process. Explosive compaction is also known as explosive sintering, and it is a powder forming technology that using shock wave generated by explosion to compact metal or nonmetal powders. Explosive compaction method is noted for its high-pressure, high-temperature and instant property, and it is the greatest potential new technology to prepare new kind of nonequilibrium materials and high-temperature ceramics.The research on preparing particle reinforced copper matrix composites by explosive compaction in this paper includes three aspect contents: theory, experiment and numerical simulation. The featured research results include:1. A new P-V relationship of condensed explosive's explosion products is obtained which form is very simple. Through the relationship we can nonlinear fit six parameters of JWL equation of state. Comparing fitted parameters with experimental parameters, it is found that fitted parameters are very accurate and can satisfy engineering application.2. A new preparation technics is proposed to manufacture particle reinforced copper matrix composites, which includes three processed: mechanical alloy, hydrogen sintering and explosive compaction. Cu-aAl₂O₃ and CuCr bulk materials are obtained by the new preparation technology. The relative density of two kinds of materials exceeds 98ï¼…, and their hardness is very high. Some appropriate technology parameters are confirmed, namely ball milling time is 20 hours, sintering time in hydrogen is 0.5 hour and explosion pressure is 4GPa through analyzing many groups experiment results.3. Research on numerical simulation of direct explosive compaction method is done by LS-DYNA program. The propagation rules of detonation wave and shock wave in compaction bulk are summarized. Mach hole is observed in numerical simulation and its formation reason is detailedly discussed. A conclusion is obtained that axial direction velocity difference between the powders in axes and edge create shear deformation such as punching hole, while shear stress is higher than shear strength limit of powders, then Mach hole will come into being in compaction bulk.4. The collapse process of circle and triangle pores in matrix bulk is simulated by finite element method. The velocity of jet penetration and oblique impact is calculated. Explosive welding will shape under high shock pressure during pores collapse, and explosive welding area is divided into three regions. The pores collapse process among particles is simulated by SPH Meshless method. Jet penetration phenomenon is observed and its velocity is obtained. Through the numerical simulation of CuCr powders, Mechanical alloy before double density and double hardness mixed particles explosive compaction is proved to be essential.