Constitutive modelling and mechanical characterization of aluminium-based metal matrix composites produced by spark plasma sintering

An effective computational tool for parametric studies and identification problems in materials mechanics

“…21 correspond to a selection of parameter values that characterize a marked anisotropic material response, singled out by the geometry of the residual imprint experiencing sinking in along direction x and piling up along y. In both investigated cases, the observed scatter is consistent with that expected from the output of instrumentation most frequently exploited to perform indentation on real materials; see, e.g., [42,43,48]. 19 Spatial distribution of the randomly generated parameters governing plastic response (initial yield limits and hardening exponent) Comparison with Lagrange interpolation was not performed in this case since an even simple cubic approximation function would require more than 16,000 (4 7 ) direct FE analyses to be carried out, each one corresponding to about 20 min computing time.…”

“…Its application ranges from nano-technological systems to large networks of pipelines for oil or gas transportation, power plants and offshore structures [8,[22][23][24][42][43][44]. In the experiment, a diamond or hard steel tip of different geometry is pressed against the surface of the material sample to be investigated.…”

“…The material response is modelled by elasticplastic constitutive laws, for instance obeying the classical Huber-Henky-Mises (HHM) or Hill [39,40] yield criterion, respectively, in the case of isotropic and anisotropic metals. Pressure dependent plasticity models are considered for ceramics and metal-ceramic composites [23,43]. Other non-linear phenomena like fracture and delamination, which may occur in the case of brittle and/or layered materials, can be further analysed by means of suitable interface laws [24,41] but are not considered to the present demonstrative purposes.…”

Mechanical characterization of metal-ceramic composites

“…Then, the unknown overall material parameters to be returned by inverse analysis are: the elastic modulus E; the initial compression yield stress 0 c  ; the internal friction angle α and the hardening modulus h. Results listed in Tab. 1 concern the case of an Al/TiB2 sample with 50% TiB2 weight content produced by spark plasma sintering in a joint research project with Inasmet-Tecnalia (San Sebastian, Spain), partner of the KMM NoE [8]. The identified parameter values are given in terms of the average and of the standard deviation of several converged optimization solutions, which returned small similar values of ( ) opt  z starting from different initial z vectors.…”

“…The composition and the production process of these composites are usually designed in order to optimize their effective thermo-mechanical response, which require to carefully control the possible presence and the evolution of local damages and defects. The estimation of macroscopic properties is often based on homogenization techniques, which often neglect microstructural details playing a significant role for brittle and quasi-brittle materials [1][2][3][4][5][6][7][8]. A proper experimental validation of the mechanical properties is therefore mandatory.…”