High strain-rate tensile properties of a TiAl alloy in duplex and fully lamellar microsturctural forms
(1. Open Laboratory ofEducation Ministry of China for High-Temperature Materials and Tests,School of Materials Science and Engineering, ShanghaiJiao Tong University,Shanghai200030,P. R. China;
2. UES, Dayton, Ohio45432, USA)
2. UES, Dayton, Ohio45432, USA)
Abstract: A self-designed Split-Hopkinson tensile bar setup with a rotating disk was used to investigate roomtemperature tensile properties of aγ-TiAl alloy in duplex (DP) and fully lamellar (FL) microstructural forms under the dynamic strain rates between 70 and 800s-1. It was found that for both forms the alloy is brittle at these strain rates, exhibiting near-zero ductility. The σb at dynamic strain rate is greater than that at the static strain rate of 5×10-1s-1, and the σb of the DP material is higher than that of the FL material. Fractography analysis indicated that both materials at dynamic strain rates fracture in a mixed mode of predominant transgranular cleavage and minor intergranular cracking, which is similar to that at the static strain rate. The roomtemperature brittleness of the alloy is not environmentally related.
Key words: titanium aluminide; tensile property; high strain rate