Effects of trace nano-TiB2 particles and multiple cooling rates on microstructure and properties of Al-4.5Cu alloy

Ceramic particles and cooling rates have important effect on the Strength and plasticity of aluminum-based materials. In this paper, the microstructure and mechanical properties of Al-4.5Cu alloy were controlled by adding ultra-trace amounts of in-situ synthesized TiB2 particles and multiple cooling rates. The results show, that the average size of TiB2 particles is about 86.35 nm. The lattice dis-registry between TiB2 and α-Al was calculated to be 4.5 %, the TiB2 particles can be used as α-Al heterogeneous nucleation cores. The average grain size and standard deviation of Al-4.5Cu alloy with the addition of 0.02 wt% TiB2 and high cooling rate are 30.5 μm and 15.9, respectively. Compared with the Al-4.5Cu alloy without adding TiB2 particles and at medium cooling rate, the average grain size and standard deviation decreased by 68.1 % and 44.2 %, respectively. It can be seen from the room temperature tensile properties of the alloy after T6 heat treatment, that the yield strength, tensile strength and elongation of the Al-4.5Cu alloys with the addition of 0.02 wt% TiB2 and high cooling rate are 468.3 MPa, 513.9 MPa, and 13.4 %, respectively. Compared with the Al-4.5Cu alloy without adding ceramic particles and at medium cooling rate, the yield strength, tensile strength and elongation increased by 15.6 %, 9.2 % and 25.2 %, respectively. •The TiB2 particles produced by the in-situ reaction are sub-micron or nano- in size.•0.02 wt% TiB2 particles and high cooling rate can significantly refine the Al-4.5Cu alloy.•0.02 wt% TiB2 particles and high cooling rate can significantly improve the strength and plasticity of Al-4.5Cu alloy.