| TZM alloy?0.4%0.55% Ti,0.06%0.12% Zr,0.01%0.04% C, Mo Bal.? possesses high melting point, high strength, low thermal expansion coefficient, excellent corrosion resistance and high temperature mechanical properties. So, it has been widely used in metallurgical industry, equipment manufacturing, defense and military industry, petrochemical, aerospace, nuclear industry and many other areas. However, the oxygen into TZM alloy will easily combine with the second phase particles to produce a larger size of oxide particle, reducing the dispersion strengthening effect, resulting in the alloy mechanical properties and processing properties were decreased, its application is limited.This paper studies the effect of TZM densification on ball-milling technology. After the experiment, studies the effect of alloy powders state on milling time, milling medium and the amount of dispersant to determine a suitable milling process conditions. The milled powders were treated as an experimental object, based on the accumulation of particles of particle size distribution optimization model to calculate the close-packed TZM alloy powder particle size distribution proportion. Respectively, regarded graphite, stearic acid?C6H36O2? and carbon nanotubes?CNTs? as carbon source added to TZM alloy and using scanning electron microscope, X ray photoelectron spectroscopy and oxygen content analyzer to Observe the alloy structure, Analysis on the distribution of elements and measure the oxygen content of the alloy. Research on the effect of TZM alloy oxygen content on three different carbon source above.The result shows that as the milling time is prolonged, the alloy powder is broken due to the repeated impact and friction, so that the particle size can be improved, and the densification degree of the alloy can be improved; Alloy powder was calculated according to the particle size of 2737 ?m?3748 ?m?4874 ?m and larger than 74 ?m four particles levels. The proportion of the close packing of the alloy powder is 9.21%: 25.12%: 26.67%: 38.94%?wt.%?. The relative density of the traditional TZM alloy is about 75%, and the relative density of TZM alloy prepared by the particle size distribution is about 90%, and the relative density of TZM alloy prepared by particle size is increased by about 15% compared with that of the traditional TZM alloy. The three kinds of TZM alloy added different carbon source, the relative density were 90.67%, 92.61% and 97.71%, using carbon nanotubes as carbon source of TZM alloy relative density is the highest. In summary, the preparation process optimization, preparation of high oxygen content of TZM alloy, the relative density of up to 97.71%, the minimum oxygen content of up to 23 ppm.In addition, the corrosion behavior of TZM and La doped TZM alloy in different corrosion medium was systematically studied in this paper. The study results shows that the corrosion rate of TZM alloy in the 3.5% HCl?wt.%? solution is 0.012 mm/a, and the corrosion resistance of the alloy is good. The corrosion resistance of TZM alloy to KOH solution was poor. In the 10% KOH?wt.%? solution, the corrosion rate is 10.420 mm/a, which is 868 times the corrosion rate in the 3.5% HCl solution. The corrosion rate of TZM alloy in 3.5% NaCl?wt.%? solution was 0.564 mm/a. Corrosion resistance and corrosion resistance in HCl solution are relatively poor. Compared with lanthanum doped TZM alloy, the corrosion potential is increased by about 0.03 V, the corrosion current density is reduced by about 2.0×10-6 A/cm2, and the doping rare earth element lanthanum can improve the corrosion resistance of TZM alloy. La2O3 and La?NO3?3 were prepared by two different lanthanum doped TZM alloy, the corrosion potential difference is only 0.001 V, the corrosion current density difference is only 0.05×10-6 A/cm2. The effect of Lanthanum on the corrosion resistance of TZM alloy was not significant. |
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