Effect of Cold Rolling and Heat Treatment on Microstructures and Mechanical Properties in Ti-13Cr-1Fe-3Al Alloys

摘要

Thermomechanical processing is effective for improving the strength and toughness in metallic materials due to grain refinement. The strengthductility balance in β-type titanium alloys can be enhanced by refinement of the β matrix grain size and α precipitation by aging. For improving the strength-ductility balance in Ti-13Cr-1Fe3Al alloys, the effects of β grain size on isothermal aging behavior and mechanical properties in Ti-13Cr-1Fe-3Al alloys were investigated. The β grain size was decreased by the following treatments: 50%CR→1073K-l.8ks,70%CR→1048K-3. 6ks and 70%CR→1048K-0. 6ks. Resistivity (ρRT and ρLN) and resistivity ratio (ρLN/ρRT) in the 84,71 and 40μm specimens started decreasing later than in the 309μm specimen with isothermal aging at 673K. Tensile properties were not sensitive to the β matrix grain size in the STQ and recrystallized states. In the STQ and recrystallized specimens,the tensile strength and elongation were roughly 800MPa and 30%,respectively. Specimens after aging showed higher tensile strength and lower elongation compared to the STQ ones. The specimen with the β grain size of 40μm after aging at 673K for 600ks showed good strength-ductility balance in all specimens.