Microstructure and Property of TiB2-Dispersed Cu-matrix Composites

In the present work, the microstructure and properties of Cu-based composites with 4.5 vol.% dispersed TiB₂ particles developed by a combined process of mechanical alloying (MA), self-propagate high temperature synthesis (SHS) and spark-plasma sintering (SPS) will be reported. The microstructure of the composites revealed that the TiB₂ dispersoids with the particle size of smaller than 250 nm uniformly distributed in Cu matrix. The sintered samples obtained approximately 99% in relative density after sintering at 650 degC for 5 min. The fine dispersed TiB₂ dispersoids in Cu matrix was the main reason to improve the mechanical properties of the composites. The hardness reached a value of 74 H_RB. The result of tensile test showed that the ultimate tensile strength, yield strength and Young modulus increased from 187 MPa, 158 Mpa and 119 GPa for pure Cu to 485.7 MPa, 355.3 MPa and 157 GPa for the composites, whereas the electrical conductivity remained a high value of 83 % IACS. After soaking at 850, 900 and 950 degC, the hardness of composites decreased to 62, 61 and 55 H_RB, respectively. The softening temperature was determined to be higher than 900 degC.