Ductile-to-brittle transition in tensile failure of particle-reinforced metals

An enhanced continuum model for size-dependent strengthening and failure of particle-reinforced composites

“…as shown in Refs. [35][36][37][38]), it would be useful to look for optimal values of material design parameters such as particle size and volume fraction.…”

Tensile elongation of unidirectional or laminated composites combining a brittle reinforcement with a ductile strain and strain-rate hardening matrix

“…(5), (6) and (24) with an evolving shear-stress in the brittle phase as expressed in Eq. (8). As in Ref.…”

“…Final fracture of the material may then happen in one of two ways. One is sudden brittle failure, caused by a propagative localization of internal damage that cuts abruptly the entire specimen in two; many strongly bonded ceramic or carbon fibre reinforced composites fail in this way [5][6][7], as do some particle reinforced composites [8]. Alternatively, internal damage accumulates stochastically throughout the material, in gradual and uncorrelated fashion.…”

“…The composite is then likely to fail by strain localization, reaching its ultimate tensile strength at a smooth maximum along its stress-strain curve, and sometimes deforming significantly thereafter, while deformation concentrates in a portion of the sample's gauge length. Weakly bonded fibre reinforced composites (e.g., [5]), ceramic particle reinforced metals (e.g., [8,9]), two-phase metal alloys [10] or laminated metal composites [11] can all fail in this way. Strain hardening and strain-rate hardening then both play an important role: even small increases in a ductile material's strain hardening rate, or in its strain-rate sensitivity, can noticeably increase the tensile elongation when it is governed by the onset of strain localization.…”

Particle fracture in high-volume-fraction ceramic-reinforced metals: Governing parameters and implications for composite failure

“…For alloyed matrix composites the linear regression was done on the first two or three modulus measurements, whereas for pure aluminium matrix composites this extrapolation was done using a linear regression between 0.2% and 0.8% plastic strain. For the pure aluminium matrix composites, we identified a difference between E 0 thus computed and values obtained by the impulse excitation technique on the undeformed composite (Hauert et al, 2009a). Using another testing machine, capable of slackfree instantaneous inversion of the loading direction, it was demonstrated that this offset is caused by microplasticity in the metal during the (finite) time interval needed for inversion of the loading direction in the MTS apparatus used here.…”