Wear of tungstenless hard alloys based on SHS-titanium carbide

The structure, porosity, strength, and wear resistance of tungstenless hard alloys based on titanium carbide are investigated. Titanium carbide is produced by self-propagating high-temperature synthesis (SHS). The strength of this alloy and normal hard alloy of similar composition is about the same, but SHS alloy exhibits higher wear resistance. The use of SHS titanium carbide alloyed with molybdenum results in an increase in strength. Addition of molybdenum to the nickel binder results in a twofold increase in wear resistance.Institute of Structural Microkinetics, Russian Academy of Sciences, Chernogolovka. Translated from Poroshkovaya Metallurgiya, Nos. 1/2(383), pp. 61–64, January–February, 1996. Original article submitted April 13, 1994.     

Finely dispersed metallic binder for tungstenless hard alloys based on titanium-niobium carbonitride

Translated from Poroshkovaya Metallurgiya, No. 7(355), pp. 79–83, July, 1992.     

Formation of the phase composition of tungstenless hard alloy powder with mechanochemical synthesis

Carbon and nickel are studied for their effect on the formation of phase composition of tungsten-free hard alloy powder prepared by mechanochemical synthesis. It is established that the phase formation of this powder is governed by the initial titanium carbide stoichiometry. If titanium carbide has a nonstoichiometric composition, the alloy structure corresponds to the three-phase equilibrium TiC_1–x-Ni₃Ti-Ni, and otherwise it corresponds to the equilibrium TiC-Ni.Translated from Poroshkovaya Metallurgiya, No. 11(359), pp. 21–24, November, 1992.     

Effect of niobium carbide on the properties of tungsten-free hard alloys

Conclusions A study was made of the effects of alloying with niobium carbide of the carbide phase of a TiC-Ni-Mo hard alloy (in amounts equal to 2,5,10, and 25 mole% relative to the TiC content) upon the physicomechanical properties of the alloy. It is shown that raising the amount of NbC in the alloy increases its transverse rupture strength (to 132 kg/mm²) and impact strength, leaving its hardness virtually unchanged (91 HRA); the improvement in properties is attributable to a slight increase in the ductility of the grains of the hard phase — a complex TiC-NbC carbide.Translated from Poroshkovaya Metallurgiya, No. 9 (129), pp. 83–86, September, 1973.     

Effect of plastic deformation on the physicomechanical properties of tungsten carbide-cobalt hard alloys

Summary A study was made of the effect of prior plastic deformation on the hardness, strength, coercive force, and electrical resistivity of tungsten carbide-cobalt hard alloys containing 10–25% cobalt. Plastic deformation decreases the hardness of the alloys. Up to a deformation of about 5–6%, all the alloys investigated showed a marked drop in hardness. Further deformation did not decrease the hardness of alloy VK25; for the alloys with lower cobalt contents, the hardness decrease was less pronounced.     

Determination of the inelastic properties of TiC-TiNi hard alloys by the ultrasonic pulsed method

Conclusions The damping properties of the TiC-TiNi alloys may be characterized by the attenuation factor of ultrasound in the megahertz frequency range. The TiNi binding phase in the hard alloy based on TiC should have a high damping effect. The addition of small amounts of boron results in the formation of a purer and denser material. We believe that the increase of the attenuation factor with the boron addition increasing to 2% is associated with the increase of the porosity of the material and not with its damping capacity.Translated from Poroshkovaya Metallurgiya, No. 7 (283), pp. 83–86, July, 1986.     

烧结温度对Mo_2FeB_2合金组织性能的影响

采用真空液相烧结法制备三元硼化物硬质合金,研究了烧结温度对三元硼化物硬质合金致密度、显微组织以及物相组成的影响.研究结果表明,三元硼化物硬质合金的密度和显微组织与烧结温度密切相关.当烧结温度较低时,合金中的硬质相晶粒发育不完全,且在粘结相中分布不均匀;烧结温度过高时,合金中的硬质相颗粒粗大,两者都会显著影响材料的性能.试样在1160～1210℃之间烧结时,随着烧结温度的不断增加,材料由固相烧结逐渐转化为液相烧结,试样的密度随着烧结温度的上升而逐渐增加,并确定试验最佳烧结温度为1210℃,此时材料的密度为8.23g/cm3,维氏硬度与洛氏硬度分别为8722.6N/mm2和75.3HRA,抗弯强度则达到1246.38MPa.通过对材料的显微组织与物相结构分析,阐述了该材料组织结构变化的原因.     

The effect of carbon content on the mechanical properties of tungsten carbide-cobalt hard alloys

Summary A study was made of the effect of graphite and-phase contents on the properties of VK8 alloy. It was found that, in the presence of the-phase in the alloy in the form of lakes or dendrites (lace), indicating carbon deficiency, the strength of the alloy is greatly reduced. Slight decarburization, taking the form of-phase formation along the interphase boundaries, has practically no effect on the strength of VK8 alloy. The presence of graphite in an amount of less than 0.5 vol. % has little effect on the wear resistance of VK8 alloy, and slightly raises its strength. A high graphite content substantially lowers both strength and wear resistance.