Development of copper dispersion-strengthened composite material with increased indexes of high-temperature strength and wear resistance for thermally loaded friction pairs

Abstract

The article presents the chemical composition, technology and general properties of copper dispersion-strengthened composite material developed by the authors based on Cu-AlC-O system with increased indexes of high-temperature strength and wear resistance for parts of thermally loaded friction units and, first of all, for valve guides of highly forced internal combustion engines and plungers of die-casting machines. This material containing 0.9 wt % aluminum, 0.3 wt % carbon has recrystallization temperature of 1000 oC and has higher tribotechnical properties comparing with standard materials. In particular, the wear out intensity of the developed material is 2.9 lower comparing to gray cast iron Gh 1051, which is used for valve guides. At the same time, wear of coupled element is also became 2.8 times less. The technology of new material is based on the method of reactionary mechanical alloying in the attritor, which provided the material with dispersion-strengthened subgrain structure with γ -Al2O3 reinforcing nanodisperse particles.

Optimization of Dispersion-Strengthened Material Based on Copper Powder for Valve Guides of Internal Combustion Engines

“…It should be noted here that the given known material with friction over a steel nitrided valve exhibited the wear out intensity of 1.12·10 -11 in the authors' study [12]. The higher wear out intensity for this material in the present tests is due to extremely high contact pressure between the sample and counterbodies.…”

“…The presently known materials are either incapable of withstanding the loads acting on them or are not readily producible. Paper [12] describes heat-resistant and wear-resistant nanostructural material based on copper powder of the Cu-Al-C-O system containing 3 % wt Al and 0.9 % wt С. A peculiarity of this material is that it, due to its subgrain structure with subgrain sizes of 90…145 nm and especially presence of dynamically thermostable particles of the strengthening phase as γ-Al2O3 with particle sizes of under 40 nm, has an extremely high recrystallization temperature (not less than 960 о С) and high hardness values at high temperatures.…”

Novel study on investigating the mechanical, microstructure morphological, and dry sliding wear characteristics of grey cast iron GG25 with copper additions for valve guides in internal combustion engine

“…It was found that the wear rate of the new material is 2.8 times less than the existing vale guide material Gh1051. This has been attributed to the formation of γ-Al 2 O 3 nano dispersed phases in the matrix resulting in improved mechanical properties (Vladimirova and Shalunov, 2020). Al-SiC (5%-30%) composites were fabricated for a novel valve guide material.…”