Acoustic emission produced by the fracture of boron particles in 2219 aluminum during tensile deformation was measured and characterized. The boron particles were introduced into the aluminum using a powder metallurgy approach. The response of an rms voltmeter to individual acoustic emission bursts was found to be proportional to the energy of the burst (integral of the squared signal voltage). The energy released by fracture of the boron particles was estimated from elasticity theory using measured diameters of the individual fractures. The energy of the acoustic emission signals produced by boron particle fracture was found to be proportional to the energy released by the particle fractures. This relation can be used to estimate the energy released by other comparable acoustic emission sources in samples of similar geometry from their acoustic emission signals.