These 1 cm x 1 cm samples of high carbon steel stuck together during austenitisation, the bonded surfaces were not prepared in any way to make them clean, so had large oxide layers.
The samples on the right were tested in 3 point bending using a small metal rod for a fulcrum and two human fingers to supply a load. With a load estimated to be several kg the samples broke apart at the bond.
Dr. Shirzadi advises that better results could be obtained by cleaning oxides from the surface, and using a load of around 10 MPa to press the samples together.
