The hot deformation behaviors of a new Ti-6Al-2Nb-2Zr-0.4B titanium alloy in the strain rate range 0.01–10.0 s⁻¹ and temperature range 850–1060 °C were evaluated using hot compressing testing on a Gleeble-3800 simulator at 60% of deformation degree. The flow stress characteristics of the alloy were analyzed according to the true stress–strain curve. The constitutive equation was established to describe the change of deformation temperature and flow stress with strain rate. The thermal deformation activation energy Q was equal to 551.7 kJ/mol. The constitutive equation was $\dot{\epsilon }{=\mathrm{e}}^{54.41}{[\sin \mathrm{h} (0.01\sigma \left)\right]}^{2.35}\exp (-551.7/RT).$ On the basis of the dynamic material model and the instability criterion, the processing maps were established at the strain of 0.5. The experimental results revealed that in the (α + β) region deformation, the power dissipation rate reached 53% in the range of 0.01–0.05 s⁻¹ and temperature range of 920–980 °C, and the deformation mechanism was dynamic recovery. In the β region deformation, the power dissipation rate reached 48% in the range of 0.01–0.1 s⁻¹ and temperature range of 1010–1040 °C, and the deformation mechanism involved dynamic recovery and dynamic recrystallization.

In this paper, a simple method to fulfill the ideal microstructural design of particle reinforced tungsten (W) alloys with promising mechanical properties is presented. W-0.5 wt.% TiC powders with core-shell (TiC/W) structure are prepared by ball-milling and controlled hydrogen reduction processes. TEM observation demonstrates that the nano TiC particles are well coated by tungsten. The W-TiC powders are sintered by spark plasma sintering (SPS) under 1600 °C. The sintered microstructures are characterized by FESEM and TEM. It is found that the W-0.5TiC alloys obtain an ultra-fine-sized tungsten grain of approximately 0.7 μm. The TiC particles with the original nano sizes are uniformly distributed both in tungsten grain interiors and at tungsten grain boundaries with a high number density. No large agglomerates of TiC particles are detected in the microstructure. The average diameter of the TiC particles in the tungsten matrix is approximately 47.1 nm. The mechanical tests of W-0.5 TiC alloy show a significantly high microhardness and bending fracture strength of 785 Hv_0.2 and 1132.7 MPa, respectively, which are higher than the values obtained in previous works. These results indicate that the methods used in our work are very promising to fabricate particle-dispersion-strengthened tungsten-based alloys with high performances.

The creep behavior of a near α TA31 titanium alloy under different compressive pressures has been studied by long-time (up to 500 h) compression tests at room temperature. The experimental results show that several thresholds of the compressive pressure were found to exist in the compression process of the TA31 alloy. When the compressive stress is lower than 0.80Rp0.2, there is no creep. There is a steady-state creep stage at the compressive stresses between 0.85Rp0.2 and 0.93Rp0.2, in which the strain rate is approximately a constant value. When the compressive stress reaches a threshold stress between 0.93Rp0.2 and 0.95Rp0.2, the sample enters the accelerating creep stage directly. The creep model of TA31 alloy has been built by using the regression method, from which the creep strain rate of TA31 titanium alloy in the steady-state creep stage under different compressive stress levels can be calculated. The mean difference between the calculated and the experimental value is 2.54%, indicating the creep model can efficiently predict the creep behavior of TA31 alloy.