V. S. Voropaev

Production of Titanium Powder Sheets by Asymmetric Rolling

The influence of symmetric and asymmetric rolling on the formation and properties of titanium powder rolled sheets is studied. It is established that the asymmetric rolling of powder metal produces sheets with higher density and much better mechanical properties than symmetric rolling does. The effect of the titanium powder rolling conditions on the structure of the material before and after sintering is studied. The rolled metal obtained by asymmetric rolling has best mechanical properties at a sintering temperature lower by 200°C than that of symmetric rolling. The technological feasibility of asymmetric rolling of titanium powder is demonstrated.

Contact stresses in the deformation zone and average pressure during asymmetric rolling of metal powders

Consideration is given to the contact normal stresses in the deformation zone on the drive rolls of different diameters rotating at the same angular speed during asymmetric rolling of iron and electrolytic titanium powders, as well as aluminum granules. The ratio of roll diameters is 1.12 to 1.42. It is established that the normal contact stresses on both rolls are much lower than those during conventional (symmetric) rolling. It is shown that during asymmetric rolling, the contact stress on the larger roll is lower than the stress on the smaller roll, regardless of the material being rolled and the density of the rolled product.

The Effect of Compacting Rolling on the Properties of Titanium Powder Mill Products

The effect of deformation stress on the consolidating of titanium powder strips obtained by symmetrical and asymmetrical rolling is analyzed. It is determined, that the strength of green strips after asymmetrical rolling is substantially higher than that of conventional strips: for low and medium deformation stress (by a factor of 3–5) and for high deformation stress (by a factor of >10). The repeated rolling improves the mechanical properties of sintered strips. Titanium powder strips produced through optimal asymmetrical rolling possess better mechanical properties than conventional titanium strips.

Finite-Element Optimization of the Asymmetric Rolling Process for Titanium Powder

The selection of resistance-to-deformation model is analyzed and justified. The results of mathematical modeling for the asymmetric rolling of titanium powder using the finite-element method are demonstrated.

Effect of Deformation Conditions on the Properties of Powder Material AMg5

The effect of deformation conditions on the structure and mechanical properties of powder materials based on aluminum-magnesium alloys produced by ultra-fast crystallization of a melt atomized by high-pressure water is studied. Extrusion of powder compacts into a strip that is then subjected to symmetric or asymmetric rolling is used as a deformation process. The effect of the rolling conditions on the mechanical properties of powder material AMg5 with Zr and Sc added is investigated. It is shown that the use of fractional rolling of strips made of AMg5 powder alloys significantly increases the ductility of the material and has a weaker effect on the strengthening; asymmetric rolling being more efficient than symmetric one.

The Influence of Deformation Modes on the Structure and Properties of Al–Mg–X Powder Composites. I. The Influence of Rolling Conditions on the Mechanical Properties of Aluminum Powder Ribbons Strengthened with SiC Nanoparticles

The influence of deformation modes on the mechanical properties of metal matrix composites produced from the aluminum powder strengthened with SiC nanoparticles has been studied. Symmetric and asymmetric rolling processes were employed at room temperature. Rolling as an additional deformation processing step improves the composite structure by refining the SiC agglomerates, asymmetric rolling being a more effective deformation processing technique. This complex hardening mechanism allows the strength to be increased twofold without decrease in the elastic and ductile parameters.

Mechanical and Fatigue Properties of Powder Titanium Strips, Obtained by Asymmetric Rolling

The mechanical properties of titanium powder strips obtained by asymmetric rolling technique are investigated. It is found out that the use of asymmetric rolling during the consolidating and repeated compacting rolling allows obtaining a strip with better mechanical properties than that obtained by conventional technique. The fracture surface of a titanium strip obtained by symmetric rolling has a significant ratio of the interparticle fracture. After asymmetric rolling, the fracture surface is totally dimpled. It is shown that the asymmetric rolling improves the quality of interparticle contact and, consequently, the ductility and fatigue resistance increase significantly.

Powder Technology for the Production of 44NKhTYu Elinvars

The paper studies the density and porosity of 44NKhTYu elinvar alloy blanks produced by powder technology, jet molding, and electron-beam remelting. It is shown that jet molding and solid-phase sintering of powders over a narrow remelting temperature range are the most promising. They can be used to make blanks and products whose density and porosity are close to those of cast alloy, the metallic yield being increased.

Properties of an aluminum-lead material produced by powder metallurgy methods processes

ConclusionsThe presence of lead and its oxides on the surface of the granules of the Al-Pb pseudoalloy leads to the formation of interphase boundaries in the form material and, consequently, impairs its mechanical and tribotechnical properties. The material with high antifriction properties was produced by extruding the mixture of the powders of aluminum and lead.

Production of clad rolled strip from granules of secondary aluminum

ConclusionsThe method of simultaneous rolling of granules and cladding foil fails to produce a continuous cladding coating. To obtain a good-quality anticorrosion aluminum coating, it is necessary to employ the method of simultaneous rolling of strip precompacted from granules of secondary aluminum alloys and foil.