Metallography in Materials Testing

In the investigation of the failure of materials, and in the analysis of both metal and plastic materials, our forensic materials laboratories use a wide range of in depth analytical techniques to reach scientifically validated conclusions.

One such technique is metallography. Through a highly refined process of sample encapsulation in resin, and gradual grinding and polishing, metallography is a technique which we use to investigate the microstructure of both metallic and non-metallic materials. The examination of the micro-structure of metallic materials can be very helpful in investigating the manufacturing process, such as heat treatment conditions, impurities in cast metals, corrosion issues or coatings failure etc.

Mechanically polished unetched surface of brass plumbing fitting.

We use metallography in many applications such as in examining the microstructure of graphite casting, investigation of heat treatment defects, corrosion issues and grain size determination.

In a most recent enquiry, we were asked to investigate the grain size of a high-strength, corrosion-resistant nickel chromium alloy which was used in the fabrication of a gas turbine engine. Using a specific metallographic preparation technique which included an etching process using Hydrochloric acid and Hydrogen peroxide, we determined that the average number of grain size number (G), was found to be 4.0 μm and perfectly within the clients quality requirement range of 3.1 to 4.7 μm.

Cross-section of leg of L.E.D. as it passing through circuit board.

We are experts in the use of metallographic techniques in the forensic investigation of materials and irrespective of the materials, such as composite materials, Tungsten, magnesium and its alloys, we have the expertise and bespoke laboratory facilities to get answers to the most seemingly technical challenges. Contact us today!