DIN 912

Outline TC4 titanium material composed of Ti-6Al-4V, is (a + b) -type titanium alloy having good mechanical mechanical properties. Than strength . TC4 intensity sb = 1.012GPa, density g = 4.4 * 103, specific strength sb / g = 23.5, and the specific strength of steel sb / g is less than 18 . Titanium alloy with low thermal conductivity . The thermal conductivity of titanium iron 1/ 5 , of aluminum 1/10, TC4 thermal conductivity l = 7.955W / m · K. Linear expansion coefficient = 7.89 * 10-6 ℃, heat = 0.612cal / g · ℃. Low modulus titanium alloy . TC4 elastic modulus E = 110GPa, steel is about 1/ 2 , the titanium alloys are susceptible to deformation. TC4 (Ti-6Al-4V) and TA7 (Ti-5Al-2.5Sn) titanium , using two injection solutions for surface modification , tests showed that titanium by ion implantation, the increase of the hardness , significantly reducing the coefficient of sliding friction , effectively improve the wear resistance. was proven its modification mechanism for injecting and non injecting samples were characterized by X -ray photoelectron spectroscopy (XPS) analysis, to obtain satisfactory results. Specimen preparation and injection conditions 1.1 Preparation of test pieces Select aero TC4, TA7 titanium , specimen into a disk shape, size is 40 * 5mm, all specimens were polished to a mirror surface . 1.2 ion implantation conditions Two kinds of titanium alloys are injected separately using two scenarios: ① In TC4 and TA7 alloy specimen sputtering Ti, Ti total film thickness of 540nm (5400A). Ti film in the plating process, and a (N + + N +2) for dynamic recoil implantation , beam energy to 50keV, beam current density is 45μA/cm2, a dose of 7 * 1017/cm2, target chamber vacuum of 1.33 * 10-2Pa; On the basis of ① ② , then into C +, beam energy of 40keV, a dose of 3 * 1017/cm2. Hardness measurement With HXD-1000 Digital measuring the microhardness is not injected into the specimen and the microhardness measured load of 4.9 × 10-2N, the measurement results are shown in Table 1 . Table 1 microhardness measurements Hardness of the material surface state / MPa hardness factor Unimplanted 26900 TC4 into (N + + N +2) 6399 1.38 Injection (N + + N +2) + C + 3436 0.28 Unimplanted 31330 TA7 into (N + + N +2) 4276 0.36 Injection (N + + N +2) + C + 4073 0.30 Seen from Table 1 , ion implantation, specimens have different degrees of hardness increase , which TC4 titanium alloy injection (N + + N +2) mixed beam hardness increases by about 1.4 times. ● TC4 Thermal expansion coefficient: TC4 titanium alloy with excellent corrosion resistance, small density , high specific strength and good toughness and weldability series of advantages, in the aerospace , petrochemical, shipbuilding, automobile, pharmaceutical and other sectors have been successfully applied . ● TC4 titanium alloy mechanical properties: Tensile strength σb / MPa ≥ 895, provides residual elongation stress σr0.2/MPa ≥ 825, elongation δ5 (%) ≥ 10, section shrinkage ψ (%) ≥ 25 ● TC4 titanium alloy density: 4.5 (g/cm3) Operating Temperature -100 ~ 550 (℃) ● TC4 titanium alloy chemical composition: TC4 titanium (Ti) balance , iron (Fe) ≤ 0.30, carbon (C) ≤ 0.10, nitrogen (N) ≤ 0.05, the hydrogen (H) ≤ 0.015, oxygen (O) ≤ 0.20, aluminum (Al) 5.5 ~ 6.8 , vanadium (V) 3.5 ~ 4.5