High-temperature titanium alloys are one of the most important research directions in the field of high-temperature aerospace alloys. They are mainly used in high-temperature-resistant components, such as blade disks, blades, and casings of aero-engines, and are key materials in a new generation of high thrust-to-weight ratio aero-engines. In the service environment of engineering applications, the creep resistance of high-temperature titanium alloys is one of the most important characteristic indicators. This paper reviews and analyzes the research status and progress on the creep properties of typical high-temperature titanium alloys in service in recent years. The effects of the creep parameters, alloy composition, and microstructure on the creep behavior of high-temperature titanium alloys are discussed, and various possible mechanisms for increasing the creep resistance of high-temperature titanium alloys are summarized.

AlCoCrFeNiTi high-entropy alloys (HEAs) have attracted much attention because of their excellent mechanical properties. Here, we systemically studied the effects of elements on the microstructure and mechanical properties of AlCoCrFeNiTi HEAs. The results showed that the phase composition and morphology are significantly affected by the elements. With increasing Ti addition, the lattice parameters of the solid solution phase increased slightly, and lattice distortion occurred. Al changes the crystal structure of FCC to BCC and reduces the lattice distortion energy of the alloy. The BCC phase obviously increases with increasing Al content. However, excessive Al, Ti and Cr promote the formation of intermetallic compound phases, while Ni, Fe and Co promote the transformation of the alloy into a solid solution. The properties of AlCoCrFeNiTi HEAs are closely related to their phase composition and morphology. When HEAs consist only of FCC and BCC phases, their ductility and strength are greatly improved. The presence of an intermetallic compound phase in the microstructure can significantly reduce the configurational entropy of adjacent solid solutions, thus reducing the strengthening effect of solid solutions. Additionally, the AlCoCrFeNiTi HEAs with different microstructures show different deformation mechanisms. The deformation of FCC + BCC HEAs with cellular structures is uniform and presents great plasticity and strength. When the cellular-structure HEAs contain equiaxed BCC, thick lamellar BCC/FCC or intermetallic compound phases, cracks tend to occur and propagate along the phase boundary due to the local nonuniform deformation. For AlCoCrFeNiTi HEAs with dendrite structures, after initiation at the phase boundary, the crack does not easily spread to the dendrite FCC phase but causes the interdendritic BCC phase to crack.

Ti-6Al-4V alloy (TC4) with different concentrations of graphene nanoplatelets (GNPs) were fabricated by ball milling and spark plasma sintering (SPS). Microstructure characteristics of the composites were characterized by X-Ray Diffraction (XRD), Scanning electron microscopy (SEM), and Raman. Microhardness and the compressive mechanical properties were also investigated. Experimental results showed that in the process of SPS, most of the GNPs were still retained at high pressure and temperature, and a new phase of TiC was presented due to the in-situ reaction between TiC and GNPs. Also, the strength of the composites was depended on the concentration of GNPs in TC4 matrix. Consequently, the composite with 0.8 wt. % GNPs was increased 18% in microhardness. The maximum yield strength and ductility of the composite were increased by 22.2% and 43.2%, respectively. The strengthening mechanism of the composites was further discussed, and the Orowan strengthening mechanism was the main strengthening factor.

Ti₂AlNb alloys with few-layer graphene were fabricated by spark plasma sintering (SPS) to enhance the tribological properties (TP) of the composite materials. Microstructure characteristics of the original few-layer graphene (FLG), Ti₂AlNb powders, and the sintered composites were characterized by X-Ray Diffraction (XRD), scanning electron microscopy (SEM), and Raman spectroscopy. The experimental results indicated that FLGs were homogeneously distributed in the composites. Tribological results indicated that the coefficient of friction (COF) of the composites was reduced as the content of FLG increased. Compared with the pure Ti₂AlNb alloy, the average COF of the composite with 1.0 wt.% FLG was decreased by 9.4% and the wear rate was decreased by 36%. Meanwhile, the microstructures of the worn surface showed that TiC particles and friction layers formed by residual FLGs were present on the surface of the composites after tribological test. It is proposed that Ti₂AlNb alloys with FLGs presented the enhanced wear resistance.

The hot deformation behavior of a new Al–Mn–Sc alloy was investigated by hot compression conducted at temperatures from 330 to 490 °C and strain rates from 0.01 to 10 s⁻¹. The hot deformation behavior and microstructure of the alloy were significantly affected by the deformation temperatures and strain rates. The peak flow stress decreased with increasing deformation temperatures and decreasing strain rates. According to the hot deformation behavior, the constitutive equation was established to describe the steady flow stress, and a hot processing map at 0.4 strain was obtained based on the dynamic material model and the Prasad instability standard, which can be used to evaluate the hot workability of the alloy. The developed hot processing diagram showed that the instability was more likely to occur in the higher Zener–Hollomon parameter region, and the optimal processing range was determined as 420–475 °C and 0.01–0.022 s⁻¹, in which a stable flow and a higher power dissipation were achieved.