Use of a viscoplastic porous solid model for the solution of hot plastic working problems

Conclusions Starting with the premises of the theory of plasticity of a porous solid and treating its matrix material as a viscoplastic Shvedov-Bingham medium, formulas have been derived for calculating densification pressure as a function of porosity, properties of the matrix material, and rate of deformation. The intensity of densification depends on the mode of loading: With increasing severity of loading for any value of porosity, the rate of densification grows, the difference becoming greater with increase in porosity. The sensitivity of a porous material to loading rate is greater in less drastic modes of loading, and grows with decreasing porosity.Translated from Poroshkovaya Metallurgiya, No. 2(266), pp. 7–13, February, 1985.     

Structure formation processes in copper-chromium-graphite P/M materials

Translated from Poroshkovaya Metallurgiya, No. 11 (347), pp. 18–21, November, 1991.     

粉末冶金铝基固体自润滑材料研究现状

铝基固体自润滑材料由于其具有优异的物理性能和摩擦性能而受到人们的广泛关注.作者从铝基体研究和固体润滑剂两方面介绍了其研究现状,并指出了发展铝基固体自润滑合金的重大意义.     

铁基粉末冶金材料烧结程度的判定

烧结过程可改进压制-烧结的铁基材料的物理-力学性能。烧结时因扩散产生颗粒结合与合金化;随着烧结时间增长,强化材料性能。烧结的作用通过显微组织特征(诸如颗粒边界与孔隙边缘)的变化可以看出。烧结的一些改进表现为颗粒边界消失,孔隙边缘变得较平滑和颗粒间尖角特征数量减少。一般将这些特征与特性的外观和它们发生的频率一起当做是烧结程度。用众所周知的体视技术(Stereological practies)与适当制备的金相试样,可以判定烧结程度。关于判定与区分烧结程度不同的材料,将讨论3种试验方法。另外,将用烧结时间不同的铁-铜-碳预混合粉材料的图像来说明这些显微组织的变化。     

Comminution of P/M materials in a vertical vibratory mill

Translated from Poroshkovaya Metallurgiya, No. 8(308), pp. 11–15, August, 1988.     

An equation for the plasticity of a porous solid allowing for true strains of the matrix material

Powder Metallurgy and Metal Ceramics -     

Determination of the ultimate plastic capacity for powder materials based on the plastic flow model for porous solids. II. Influence of porosity and the stress-strain properties of the solid phase on the ultimate plastic capacity of a porous sintered material

A procedure for theoretical construction of the limiting surface for porous materials is described. The procedure requires the porosity, the stress-strain properties of the solid phase, and decohesion to be predefined. The limiting surface is defined for proportional loading paths. The obtained limiting states are also represented as plasticity diagrams. A satisfactory correspondence of the theoretical results with experimental data is shown for a number of both ferrous and non-ferrous powder materials. Translated from Poroshkovaya Metallurgiya, Nos. 1–2(411), pp. 9–13. January–February, 2000.