Titanium (Ti) and its alloys possessing high specific strength, specific stiffness, good heat and corrosion resistance, and a relatively low density are widely used as structural materials in aviation, aerospace, automotive, biomedical, and many other industry fields. [1][2][3] TiÀ6AlÀ4V (TC4) is the most representative Ti alloy because of its overall excellent room-temperature properties. [4,5] However, the high-temperature mechanical properties of the TC4 alloy are relatively poor. The current working temperature of TC4 is lower than 500 C, which is much lower than some other alloys such as steel and nickel-based superalloys. [6,7] In addition, Ti alloys usually have poor electrical and thermal conductivity (around 10 W/ (m K)), [8] which greatly limits their applications. [9][10][11] Introducing reinforcements with high strength and high thermal conductivity in Ti alloys to make a Ti matrix composite (TMC) is an effective method to improve its overall properties. [12][13][14] Carbon fiber (CFs) is a fiber material with excellent physical, mechanical, and thermal properties. Its diameter is on the level of several micrometers, while the length can reach up to centimeters. This characteristic makes them not only possess high aspect ratios but also be easier to disperse homogeneously in metal matrices compared with nanocarbon reinforcements. [15][16][17] The density of CFs is only %1.80 g cm À3 (40% of Ti) but the axial tensile strength of CFs is above 3.5 GPa (>300% of Ti). CFs' high-temperature resistance ranks among the top in all chemical fibers, [18] which are shown to be ultrahigh temperature (over 2000 C) resistant in the nonoxidizing environment. Last but not least, the thermal conductivity of CFs is around 5000 W/(m K) (%500 times of Ti). Therefore, CF is a promising reinforcement to prepare high-performance TMCs, which can be expected to make up the aforementioned shortcomings of Ti alloys.Currently, continuous long CFs are often applied to fabricate high-strength TMCs. [19][20][21][22][23] Even et al. [24] adhered long CFs on the surface of titanium alloy powder by viscous organic polymers and then used hot isostatic pressing (HIP) to produce continuous CFs-reinforced TMCs under the conditions of 600À700 C, 200 MPa, and 1 h. The composites were all above 98% in density and the ultimate tensile strength (UTS) reached 600 MPa at room temperature. Yang et al. [25] used copper-coated continuous CF cloth as reinforcement and TC4 as matrix. After they were compressed and stacked on top of each other, CF cloth/TC4 composites were manufactured by spark plasma sintering (SPS). The compressive yield strength (YS) increased by 370 MPa compared with TC4 matrix at a strain rate of 4200 s À1 because of the tight interface bonding. Overall, the fabrication process of the aforementioned continuous CFs-reinforced TMCs is complicate. In addition, they can only achieve good performance in certain specific directions, showing anisotropic characteristics.
