The laboratory facilities within the Centre for Materials Engineering enable full characterisation and testing of most engineering materials. The laboratories are geared towards both undergraduate teaching and advanced research at postgraduate and post-doctoral levels.
The main facilities include:
Researchers at the Centre are also able to access other facilities on UCT campus and designated regional facilities within the Western Cape. These facilities include the Electron Microscope Unit at UCT and the X-ray Diffraction system at the National Acceleration Centre.
Corrosion Testing
Facilities for corrosion testing include a wide range of techniques to monitor static corrosion. Potentiostatic and potentiodynamic testing is carried out on a Versastat 3 instrument from Princeton Applied Research and allows the determination of environmental conditions that cause general or localised corrosion. Laboratory simulation of environmental conditions can be carried out in a Q-Fog Cyclic Corrosion tester, which can be programmed to carry out alternate wetting and drying cycles to exactly replicate conditions such as those experienced in a car exhaust system.
Heat Treatment
The heat treatment facility includes a sophisticated high vacuum/controlled atmosphere quenching furnace capable of performing heat treatments up to 1200°C. Various salt baths for isothermal treatments are also available, as well as a number of muffle furnaces capable of performing atmospheric heat treatments up to 1100°C.
Mechanical Testing
The mechanical testing facility has a 250/50kN servo-hydraulic machine (ESH), a 200kN Zwick universal testing machine, an impact testing machine capable of measuring both Izod and Charpy fracture energies, and a 5kN Instron tension/compression tester.
A Gleeble 3800 was purchased with the proceeds of a special award by NRF in 2011. The Gleeble 3800 is a fully integrated digital closed-loop control thermal and mechanical testing system. It provides a user-friendly interface to create, run and analyse data from thermo-mechanical tests and physical simulation programs for the testing of metallic materials. The direct resistance heating system of the Gleeble 3800 can heat specimens at rates up to 10 000°C/sec up to a temperature of 3000°C, and can hold steady-state equilibrium temperatures with excellent tolerances. High cooling rates can be applied to quench after testing. The mechanical system is a fully integrated servo-hydraulic system capable of exerting up to 20 ton (200kN) in compression and 10 ton (100kN) in tension. Displacement rates as fast as 2000mm/sec can be achieved. The system is fitted with the standard module for uniaxial compression and tension testing which also satisfies the requirements for performing controlled heat treatments including solidification and welding simulations. The HYDRAWEDGE module is also available to closely simulate multi-step industrial metal processes including hot rolling, forging and extrusion.
Microscopy
The light microscope laboratory is geared for incident and transmitted light microscopy. The principal research microscope has a video camera attached for the acquisition of high quality digital images.
The Centre also has access to a suite of electron microscopes at the Electron Microscope Unit at UCT, listed below:
FEI Tecnai F20 TEM:
200kV field emission gun (FEG) high resolution TEM,
Cryo facilities,
3D TEM technology
FEI Tecnai T20 TEM:
200 kV LaB6 electron source
Cryo Facilities
Objective Lens: FEI Super twin
Zeiss912 TEM:
An Energy Filtered TEM (EFTEM)
Electron Energy Loss Spectroscopy (EELS)
Nova nanoSEM:
Field Emission Gun,
Backscatter detector,
EDS detector
EBSD system
Low vac capabilities
Leo S440 SEM:
LaB6 electron source
Backscatter detector
EDS system
Cryo facilities
Specimen Preparation
The Centre has a modern, well-equipped laboratory for the preparation of specimens for microstructural analysis. The Struers Metalog system is employed, and grinding and polishing media are maintained for the preparation of a broad spectrum of material types that range from polymers to hard metals and wear resistant ceramics. Facilities for the preparation of thin foil specimens for transmission electron microscopy include a Struers Tenupol twin jet polisher and a Gatan Precision Ion Polishing System (PIPS).
Custom designed equipment and test specimens are manufactured in a precision machine workshop that is housed within the Centre.
Thermal Analysis
The Centre has a NETSCH STA400 thermal analyser that is capable of performing simultaneous TG/DTA and TG/DSC analysis at temperatures up to 14000C. The system is configured for vacuum and controlled gas environment. The phase transformation behaviour of materials can also be characterised using a custom-built digital dilatometer in both vacuum and controlled atmospheres.
Wear Testing
Abrasive Wear
Abrasion occurs during relative motion of contacting surfaces which are significantly dissimilar in hardness. If the harder surface is relatively rough then the result will be ploughing and cutting of material from the less hard surface.
In two body abrasion the test is carried out using a pin on belt apparatus. A specimen is locked into a bracket and placed into contact with an abrasive belt. The belt moves continuously in one direction while the specimen moves across the belt. In this way the specimen surface is always in contact with fresh abrasive. The contact load, speed and type of abrasive can be varied.
Sliding Wear
In the reciprocating sliding wear test the wear specimen is mounted onto a shuttle base and reciprocates continuously against a particular counterface. The counterface can be ground to a specific surface roughness value. Test can be conducted under dry or lubricated conditions. The sliding motion is linear whillst the sliding velocity is sinusoidal. The frictional force can also be measured.
In pin-on-disk wear test the counterface disc is mounted onto a shaft or disc driven by an electric motor. The wear pin is loaded against the counterface by a simple pivot arm system. The interfacial pressure can be adjusted and test can aslo be conducted under lubricated conditions. The sliding velocity is constant whilst the grinding direction on the counterface changes with respect to the motion of the pin. The frictional force is measured by a load cell restraining tangential movement of the specimen clamp.