Effect of Solution-ECAP-Aging Treatment on the Microstructure and Properties of TB8 Titanium Alloy

Abstract

The microstructure and mechanical properties of the TB8 titanium alloy were controlled by a secondary processing technology of solution-equal channel angular pressing (ECAP)-aging treatment, which combined strong plastic deformation with heat treatment. The effects of ECAP and heat treatment on the microstructure and properties of the titanium alloy were systematically investigated by optical microscopy (OM), scanning electron microscopy (SEM), hardness tests, and tensile property analysis. The results indicate that the metallographic structure without ECAP treatment is mainly equiaxed β-phase, while that after ECAP treatment is equiaxed β-phase with grain fragmentation, slip bands, and new small grains. After 850 °C solution-ECAP-520 °C aging treatment, the titanium alloy has the smallest grain size, while the directionality of tissue growth along the ECAP direction is the most apparent. Under the same solution-aging conditions, the hardness of the titanium alloy increases from 431.5 to 531.2 HV compared to that without ECAP treatment, i e, increases by 23.11%, and the tensile strength increases from 1 045.30 to 1 176.25 MPa, i e, increases by 12.5%.

Keywords

equal channel angular pressing / heat treatment / TB8 titanium alloys / microstructure / mechanical properties

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