A new stroboscopic neutron diffraction method for monitoring materials subjected to cyclic loads: Thermal cycling of metal matrix composites

摘要

The use of Bragg diffraction techniques to determine the elastic strain state and thus the stress within a material has been established for several years (1). Neutrons have the advantage over the more widely used x-rays of greater penetration depth (e.g. half depth of ~20mm in Al, c.f. ~20um for x-rays of comparable wavelength (2)), allowing monitoring of bulk properties without the need for surface corrections or sectioning (3). However to date, long data acquisition times have hamstrung time resolved studies. In this paper we present a new stroboscopic method for the monitoring of rapid cyclic phenomenon and use it to study the internal strain changes occuring in an Al/10%SiC whisker composite during thermal cycling.