Development of Unidirectional Cellular Structure with Multiple Pipe Layers and Characterisation of Its Mechanical Properties

This study is concerned with the development of a new unidirectional cellular (UniPore) copper structure with multiple concentric pipe layers. The investigated UniPore structures were grouped into three main types, each having a different number of pipes (3, 4, and 5 pipes per transversal cross-section) and different pore arrangements. The specimens were fabricated by explosive compaction to achieve tightly compacted structures with a quasi-constant cross-section along the length of the specimens. The bonding between copper pipes was observed by a metallographic investigation, which showed that the pipes and bars were compressed tightly without voids. However, they were not welded together. The mechanical properties were determined by quasi-static compressive testing, where the typical behaviour for cellular materials was noted. The study showed that porosity significantly influences the mechanical properties, even more so than the arrangement of the pipes.

Suitability of laminated steel-copper structure for high-pressure hydraulic manifolds

Vacuum brazed steel-copper laminate could be used in high-pressure hydraulic manifolds in order to reduce size, weight and allow use of complex designs. The durability of such material is unknown. Samples were manufactured and static and dynamic tests were conducted. Results showed reduced material performance due to heat treatment. A hydraulic test manifold was manufactured and a long-term pressure load test was conducted. The material showed surprisingly good durability and pressure hull did not break in tests. A microscopic study was performed and only solidified copper in the corners had micro cracks after 10 million test cycles.

Analysis of the stress-strain state of copper M0B under different schemes of equal channel angular pressing and its effect on the structure and physical and mechanical properties

The results of studies of the stress-strain state of copper M0b after deformation under different schemes of equal channel angular pressing (ECAP) are presented. The level of macro and micro stresses in copper has been determined in various ECAP modes. It is shown that the strength properties, deformation porosity and parameters of the fine copper structure differ depending on the loading pattern.

CYCLIZATION OF MATRIX COPPER-BASED ELECTRODES IN NITRIC APROTIC SOLUTION OF CALCIUM SALT

Influence of calcium compounds in the structure of copper matrix preliminary modified with transition metals on the cyclization of CuCa, CuBiCa, CuPbBiCa electrodes in nitric aprotic solution of calcium salt was studied. The composition of forming calcium compounds in the copper structure and electrochemical copper-based alloys was found by X-ray analysis.