Local stress and strain in heterogeneously deformed aluminum: A comparison analysis by microhardness, electron microscopy and finite element modelling

Abstract

The local stress and strain are analysed in a heterogeneous microstructure induced by compression of aluminium rings under nearly full sticking conditions. This analysis is based on characterization of mechanical behaviour and microstructure applying three complementary techniques covering multiple length scales: microhardness, electron microscopy (electron backscatter diffraction) and finite element modelling.The findings are underpinned by applying those techniques in an analysis of a homogeneous microstructure induced by compression of hot-extruded aluminium cylinders. The local stress and strain are estimated at 14 different positions in two rings representing large variations in strain. A comparison with the stress and strain in the homogeneously compressed cylinders related to the average spacing between deformation induced low and high angle boundaries, validates the characterization techniques and supports a hypothesis that the microstructure of local regions in a heterogeneous structure evolve in accordance with universal principles and mechanisms established for the evolution of the deformation microstructure of polycrystalline metals.

Carburization induced extra-long rolling contact fatigue life of high carbon bearing steel

“…The sample microstructure was characterized by optical microscopy and scanning electron microscopy (SEM), electron backscatter diffraction (EBSD) and X-ray diffraction (XRD). The details for sample preparation can be found elsewhere [18][19][20][21][22].…”

Friction condition of aluminum alloy AA6061 lubricated with bio-lubricant in cold forging test

“…According to Zhang et al (2019), there is no specific standard for deciding how to align experimental findings with the most appropriate calibration bend, which is critical for evaluating interaction conditions. Equation 4 was characterized to assess the friction conditions and e = 0.005 or 0.5% was acknowledged as the small positive number: where d Exp is diameter for inner part and δd Exp is diameter inner part of reduction percentage, respectively.…”

“…The low energy dislocation structure approach was used to analyse the boundaries' origin and development. According to Zhang et al (2019), to illustrate this heterogeneity, seven boxed areas with edge lengths of approximately 50 m m have been labelled 1-7 in the strain distribution figures shown in Figure 5. The result shows the formation and stress effective of the all-ring specimen at 40% deformation under projected Tresca shear friction.…”

“…Friction incorporates a critical impact on tribological study and metal forming processes. According to Zhang et al (2019), the standard models, for example, Tresca friction (equation 1) are usually used to view friction when there is interaction between the workpiece and the die: where p is the normal pressure, K is the yield stress in shear, τ is the frictional shear stress and m is the Tresca shear friction.…”

Interactions between Dislocations and Boundaries during Deformation

“…Since the IDBs are assumed to be penetrable to slip and contribute via the forest hardening. Meanwhile the GNBs are assumed to be barriers to slip and contribute by the Hall–Petch strengthening [ 163 , 164 ]. The flow stress is the sum of friction stress, forest and Hall–Petch hardening, which can be expressed as: where f GNB is the fraction of GNBs, M is the Taylor factor, α is a constant, μ is the shear modulus, b is the Burgers vector and θ IDB is the average misorientation angle of IDBs.…”