Shout out for Acoustic Emission in Failing Materials – Kirkaldy Museum

The Kirkaldy museum in London have been torturing some materials using artists and test equipment.

The Kirkaldy museum preserves testing machines designed to perform mechanical tests on finished engineering components. It is the site of the testing house established by David Kirkaldy (1820–1897) a Scottish engineer who pioneered the testing of materials as a service to engineers during the Victorian period. In Southwark, London, a large hydraulic tensile test machine was constructed to measure the mechanical properties of engineering components.

The moto of Kirkaldy’s test house was “Facts not opinions”.

The Kirkaldy works tested components for the 1874 Eads Bridge across the Mississippi River, and for the Skylon that was built for the nearby Festival of Britain in 1951. It also helped accident analysis by tested materials from structures that failed, including the Tay Bridge Disaster of 1879 and the BOAC Flight 781 De Havilland Comet crash of 1954.

Eads Bridge, St Louis

Eads Bridge, St Louis (image from wikipedia)

The Skylon

The Skylon (image from wikipedia).

Dyanamic test austempered ductile iron

Drs Dawid Myszka, A. Wieczorek and Tadeusz Cybula from the Warsaw University of Technology, Poland investigated the influence of microstructure on the dynamic mechanical properties of austempered ductile iron using Taylor impact testing. Austempered dictile iron means it’s a cast iron, so has graphite particles in a matrix heat treated to become bainite!. Taylor impact testing means you fire cylinders of the material at an immovable object and see how the material gets squished.

Deforming Austempered Ductile Iron

Shattering Austempered Ductile Iron

The heavily deformed volume which faced the impact has resulted in hardening and in transformation to martensite — both hardness and magnetic measurements have been used. Hardening was due to mostly strain induced austenite-to-martensite transformation, and also due to cold-work.

References
D. Myszka, L. Cybula and A. Wievzorek
Influence of heat treatment conditions on microstructure and mechanical properties of austempered ductile iron after dynamic deformation test
Archives of Metallurgy and Materials
V59, Issue 3, 2014

DOI:10.2478/amm-2014-0204