High strain rate superplasticity of TiNp/1N90Al composite prepared by powder metallurgy method
(3.National Industrial Research Institute of Nagoya, Nagoya 462, Japan)
Abstract: TiNp/1N90Al composite was fabricated by powder metallurgy method with a reinforcement volume fraction of 15%. The tensile experiment, DSC and SEM were used to study the high strain rate superplasticity of the TiNp/1N90Al composite. The DSC result shows that the incipient melting temperature of the TiNp/1N90Al composite is 906K. The tensile tests were carried out over a range of deformation temperature from 918 to 928K and strain rate from 1.7 to 1.7×10-3 s-1. The maximum elongation of 201% is realized at 923K with a strain rate of 1.7×10-1 s-1. Otherwise all the elongations are higher than 100% in the strain rate range of 3.3×10-2-6.7×10-1 s-1 at the three deformation temperatures. The curves of m value of the TiNp/1N90Al composite can be divided into two stages with the variation of strain rate at different deformation temperatures and the critical strain rate of 10-1 s-1. When the strain rate is higher than 10-1 s-1, the m values of the three curves are smaller than 0.3, but the m values of the three curves are about 0.37 when the strain rate is higher than 10-1 s-1.
Key words: high strain rate superplasticity； metal matrix composite； hot rolling deformation； microstructure