A comparative investigation of the properties of nickel-graphite materials from electrolytic and carbonyl nickel powders

Summary The substitution of carbonyl nickel powder for electrolytic powder raises the strength, as well as the corrosion and oxidation resistance of nickel-graphite materials. The particle size and ash content of the graphite exert no marked influence on the strength characteristics.Translated from Poroshkovaya Metallurgiya, No. 11(47), pp. 35–38, November, 1966.     

The mechanical properties of materials from iron powder obtained by the reduction of martite ore

Conclusions The article presents the results of an investigation of the mechanical properties of samples of iron powder obtained by reducing martite ore by converted natural gas.The use of this raw material for producing iron powder for the needs of the powder metallurgy industry permits a considerable extension of the raw material reserves.As a result of the investigations the authors determined the characteristics of strength, plasticity and fatigue strength of material of varying porosity.The regularities of deformation of such materials and the strength characteristics of the duration of load application were studied.The results show that the strength and plasticity of metal powder materials of similar composition made of other kinds of iron powders.     

Microstructures and properties of nanocomposites obtained through SPTS consolidation of powders

The microstructures and properties of copper- and aluminum-based nanocomposites processed through severe plastic torsional straining (SPTS) consolidation of metallic micrometer powders and ceramic nanopowders were investigated by transmission electron microscopy (TEM), X-ray diffraction (XRD), microhardness and electrical resistivity measurements, and mechanical tests. It was shown that the SPTS consolidation of powders is an effective technique for fabricating metal-ceramic nanocomposites with a high density, ultrafine grain size, and high strength. Copper samples processed under a high pressure of 6 GPa exhibited high failure strength and strain as well as unusual strain hardening. Superplastic-like behavior was found in Al-Al₂O₃ nanocomposite samples. This article is based on a presentation made in the symposium “Mechanical Behavior of Bulk Nanocrystalline Solids,” presented at the 1997 Fall TMS Meeting and Materials Week, September 14–18, 1997, in Indianapolis, Indiana, under the auspices of the Mechanical Metallurgy (SMD), Powder Materials (MDMD), and Chemistry and Physics of Materials (EMPMD/SMD) Committees.     

Hot rolling of blanks from copper and nickel powders

Summary The authors investigated the hot rolling of preformed blanks from electrolytic copper and carbonyl nickel powders. The blanks were prepared by cold pressing, cold rolling, wedge pressing, and sintering loosely poured powder. The hot rolling was carried out in a special mill, in a hydrogen atmosphere. The investigation showed that at high rates of deformation, a rolling temperature of 0.8–0.9 T_melt, and a reduction of 50% the hot rolling of preformed copper and nickel blanks in one pass can yield strip with a relative density of 100%, a fine-grained structure, and mechanical properties which are not inferior to those of materials obtained by sintering powder compacts or cold-rolled strip.Translated from Poroshkovaya Metallurgiya, No. 6 (66), pp. 25–28, June, 1968.     

Effect of storage on the properties of ultrafine nickel and copper powders

Conclusions Storage of ultrafine powders under unfavorable conditions, in particular in air, adversely affects their processing properties, bringing about marked changes in their compressibility and sinterability. Storage in argon of technical purity does not offer effective protection to particles against surface oxidation. Storage of UFPs in the form of compacts of relative density 0.5–0.6 almost completely inhibits the powder oxidation process, and granulated powders produced by disintegrating compacts possess superior processing characteristics A simple method is proposed for estimating the oxygen content of a powder from the electrical resistivities of compacts.Translated from Poroshkovaya Metallurgiya, No. 10(274), pp. 74–78, October, 1985.     

红土镍矿加压浸出工艺残积型红土镍矿中和试验研究

残积型红土镍矿是一种重要的红土镍矿,镁元素含量较高(10％～27％),在红土镍矿加压浸出项目中,通常用来中和加压浸出的矿浆,矿浆中硫酸浓度通常为30 ～ 50 g/L.但残积矿用量对镍、钴浸出率有较大影响,为了更好地利用残积型红土镍矿,本文进行了常规浸出试验和还原浸出试验.试验结果表明:随着残积矿用量的增加(液固比降低...