Preparation And Characterization OF B4C/6061Al Composite Plates

With large dimensions find wide applications in the fields of aerospace, automobile, defense and so on. Powder metallurgy is considered to be one of the most effective technologies to produce such materials. In many particle reinforced aluminum matrix composites, SiC is the most frequently used reinforcement. Compared to SiC, the density of B4C ceramics is lower (2.5g/cm’), a higher hardness (second only to diamond and cubic boron nitride),and good neutron absorbing ability. Using the appropriate preparation process, B4C/Al composites has a higher strength, abrasion resistance, and also has the ability of neutron absorption, become advanced materials with structure and function.In this paper,hot pressing and rolling process of B4C/6061A1composite are explored. Optical microscope, SEM, XRD and EDS were applied to observe the microstructure and fracture face of B4C/6061A1. In the situation of the same mass fraction of reinforcement (30wt%), the regular pattern of the tensile strength of B4C/6061A1which changed with the particle size of B4C are studied.The main resultsa are listed as follows:1.Vacuum sheath prepared by cold pressing billet successive hot pressing; Vacuum temperature is450℃, the pressing temperature is600℃, prepared (30wt%)1000×260×40mm3square billets successfully, The as-prepared preforms were characteristic of excellent microstructure homogeneity combined with fine grain and uniform distribution of B4C particles.2. The30wt%B4C/6061Al plate rolling experiment indicated that the open rolling temperature is450℃, the final rolling temperature370℃. The first three passes reduction between10%to15%, the reduction of the middle road for 20%to25%, after the degree of deformation of composite materials larger than70%, the composite density reached99.39%,further rolling does not make the density change.3. Composite sheet by hot rolling, the broken B4C particles emerge in base body, the particle size decreases, particle cusp showed passivation trend. With the increase of rolling reduction, the internal porosity of the composites healing become obvious, the macro performance is density increase. The density of the composite material and its distribution in the plate in the position of the middle slightly larger than the density of the sample, the plate edge the sample of density is slightly smaller.4. With increasing of particle size on the basis of the distribution and interfaces of B4C in6061aluminum alloy matrix which combines the features and strengthening mechanisms to compare the impact of different grain size of B4C Composites, The results indicated that with the B4C particle size decreased, the density decreased, and the tensile strength increased. While adding mixed B4C particles, defects in the specimen decreased,the density increased significantly, the tensile strength increased by18%than others; The result of tensile test indicates that the tensile strength of all the longitudinal specimens increased by15%than transverse specimens.