Search results

Sort By:

Limit search:

Microstructure and Properties of Spark Plasma Sintered Al-Zn-Mg-Cu Alloy

100%

Becker H., Dopita M., Stráská J., Málek P., Vilémová M., Rafaja D.

Acta Physica Polonica A

2015

vol. 128

issue 4

602-605

The microstructure of an aluminum alloy containing 53 wt% Zn, 2.1 wt% Mg and 1.3 wt% Cu as main alloying elements has been studied with the focus on the precipitation behavior during the spark plasma sintering process. The starting material was an atomized Al-Zn-Mg-Cu powder with the particle size below 50 μm. The particles showed a solidification microstructure from cellular to columnar or equiaxed dendritic morphology with a large fraction of the alloying elements segregated in form of intermetallic phases, mainly (Zn,Al,Cu)₄₉Mg₃₂ and Mg₂(Zn,Al,Cu)₁₁, at the cell and dendrite boundaries. The microstructure of the sintered specimens followed the microstructure of the initial powder. However, Mg(Zn,Al,Cu)₂ precipitates evolve at the expense of the initial precipitate phases. The precipitates which were initially continuously distributed along the intercellular and interdendritic boundaries form discrete chain-like structures in the sintered samples. Additionally, fine precipitates created during the sintering process evolve at the new low-angle boundaries. The large fraction of precipitates at the grain boundaries and especially at the former particle boundaries could not be solved into the matrix applying a usual solid solution heat treatment. A bending test reveals low ductility and strength. The mechanical properties suffer from the precipitates at former particle boundaries leading to fracture after an outer fiber tensile strain of 3.8%.

Mechanical and Thermal Properties of Individual Phases Formed in Sintered Tungsten-Steel Composites

100%

Matějíček J., Nevrlá B., Čech J., Vilémová M., Klevarová V., Haušild P.

Acta Physica Polonica A

2015

vol. 128

issue 4

718-721

Tungsten is a prime candidate material for plasma facing components in fusion devices, thanks to its advantageous properties with respect to interaction with hot plasma. For its bonding to the supporting structure, composites and graded layers can be used for the reduction of stress concentration at the interface. When tungsten and steel are processed at elevated temperatures, e.g. hot pressing or spark plasma sintering, intermetallic phases may form and their presence and properties will affect the properties of the composite. In this work, mechanical and thermal properties of the individual phases, i.e. steel, tungsten and Fe-W intermetallics are investigated. Mechanical properties were determined by instrumented indentation. Thermal conductivity was determined by the xenon flash method on a range of samples with varying composition, from which the conductivities of each constituent were estimated. The results can be used for the optimization of compositional profiles and processing conditions for manufacturing of plasma facing components.

Refine search results

2 Acta Physica Polonica A

2 2015

2 Vilémová M.

1 Becker H.

1 Dopita M.

1 Haušild P.

1 Klevarová V.

1 Matějíček J.

1 Málek P.

1 Nevrlá B.

1 Rafaja D.

1 Stráská J.

1 Čech J.

Search results

Microstructure and Properties of Spark Plasma Sintered Al-Zn-Mg-Cu Alloy

Mechanical and Thermal Properties of Individual Phases Formed in Sintered Tungsten-Steel Composites