Cu-MgO Composites

Metal matrix composites reinforced with ceramic particles can be interesting for a range of applications due to their strength performance at high temperatures and a relatively low thermal expansion potential.
Manufacturing of Cu-MgO composites critically requires that the raw materials have a very high level of purity (99.5-99.9%) to achieve the desired manufacturing results. Continue reading

Iron Spark Plasma Sintering (SPS): Part One

Spark Plasma Sintering (SPS) is a sintering technique which is well matched to mechanically milled materials such as tool steels due to its low temperature and short cycle time.
Tool steels have been specifically manufactured to exhibit exceptionally high strain hardening, a characteristic which can be undone by high temperature sintering processes such as hot isostatic pressing. Continue reading

Semi-Solid Rheocasting of Alumina Alloys: Part One

Aluminum is well established at the front of the pack with regards to providing the technological answer to the increasing challenges of light weighting whilst maintaining integrity of the material for the desired applications.
Semi solid rheocasting is a development within the casting sector which enables improved quality in die casting without increasing cost. Continue reading

Forging

Forging was the first of the indirect compression-type process and it is probably the oldest method of metal forming. It involves the application of a compressive stress, which exceeds the flow stress of the metal. The stress can either be applied quickly or slowly. The process can be carried out hot or cold, choice of temperature being decided by such factors as whether ease and cheapness of deformation, production of certain mechanical properties or surface finish is the overriding factor.
There are two kinds of forging process, impact forging and press forging. In the former, the load is applied by impact, and deformation takes place over a very short time. Press forging, on the other hand, involves the gradual build up of pressure to cause the metal to yield. The time of application is relatively long. Over 90% of forging processes are hot.

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High Temperature Materials

The subject of high temperature materials is a very broad topic indeed. When a material is used at elevated temperatures, its strength, as reflected in tensile strength, stress rupture life, or fatigue life, is of prime importance.
Currently, there are three main categories of superalloys that include iron (iron nickel)-based, nickel-based, and cobalt-based alloys.

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Silicon Carbide (SiC): Part One

Originally produced using a high temperature electro-chemical reaction of sand and carbon, silicon carbide is recognized as one of the most promising structural materials due to its excellent high temperature strength, good oxidation, and thermal shock resistance to name just a few advantages.
The secret of these excellent attributes lies in the composition of the material which is composed of tetrahedra of carbon and silicone atoms which inherently display extremely strong bonds within the crystal lattice.

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