A new type of dislocation loop in quenched platinum

Abstract

A new type of secondary defect has been observed in quenched degassed platinum by transmission electron microscopy. The defects, which are formed by direct quenching to high temperatures, are faulted vacancy loops which, rather surprisingly, lie on the (100) cube planes. The loop Burgers vector is inferred to be a/2 (100) normal to the loop plane. The more usual faulted and perfect (111) loops are formed during vacancy precipitation at lower temperatures. The results are compared with recent observations of (100) loops in quenched stainless steel and the significance of residual gases in defect cluster formation is also briefly discussed.