Microstructure and mechanical properties of Ti−43Al−9V alloy
fabricated by spark plasma sintering
fabricated by spark plasma sintering
(1. School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China;
2. National Key Laboratory for Precision Hot Processing of Metals,
Harbin Institute of Technology, Harbin 150001, China)
2. National Key Laboratory for Precision Hot Processing of Metals,
Harbin Institute of Technology, Harbin 150001, China)
Abstract: A fine-grained TiAl alloy with the composition of Ti−43Al−9V was prepared by mechanical milling and spark plasma sintering (SPS). The relationship among sintering temperature, microstructure and mechanical properties was studied. The results show that the morphology of mechanical milling powder is regular with size in a range of 5−30 μm. Main phases of γ-TiAl, α2-Ti3Al and few B2 phase are observed in the SPS bulk samples. For samples sintered at 1150 °C, equiaxed crystal grain microstructure is achieved with size in a range of 300 nm−1 μm. With increasing SPS temperature to 1250 °C, the size of equiaxed crystal grains obviously increases, the microhardness decreases from HV592 to HV535, and the bending strength decreases from 605 to 219 MPa. Meantime, the compression fracture strength also decreases from 2601 to 1905 MPa, and the strain compression decreases from 28.95% to 12.09%.
Key words: TiAl alloy; mechanical alloying; spark plasma sintering; microstructure; mechanical properties