Dispersion of TiC particles in an in situ aluminum matrix composite by shear plastic flow during high-ratio differential speed rolling

Effect of Grain Refinement and Dispersion of Particles and Reinforcements on Mechanical Properties of Metals and Metal Matrix Composites through High-Ratio Differential Speed Rolling

“…Figure 8 compares the strain along the thickness of sheets produced by ESR and HRDSR techniques for a thickness reduction of 70% with a single pass at SR = 3 [ 46 ]. The shear strain here has been calculated based on the strain increments.…”

“…The effective shear strain, which is applied through HRDSR, not only refines the grain size of metals and alloys but also can effectively disperse the micro- and nanosized reinforcements in the metal matrix composites, which is critically important for the strengthening of the metal matrix composites. An attempt for the development of an in-situ aluminum matrix for compositing with TiC as reinforcement has been carried out by Kim et al [ 46 ], where the cast composite was subjected to several steps of conventional rolling (ESR) and then HRDSR. As can be seen in Figure 19 , conventional rolling was not so effective in the dispersion of the clusters of TiC particles, even after 14 passes ( Figure 19 c), but HRDSR resulted in effective particle distribution, even after a single ( Figure 19 d) and especially after two passes ( Figure 19 e).…”

“… ( a ) The analyzed points in the enmeshed domain of simulation and ( b ) the accumulated shear strain along the thickness of the sheet using finite element simulation for HRDSR with SR = 3 for a thickness reduction of 70% by a single pass [ 46 ]. Reproduced with permission from Kim et al, Mater.…”

Al-TiC Composites Fabricated by a Thermally Activated Reaction Process in an Al Melt Using Al-Ti-C-CuO Powder Mixtures: Part II. Microstructure Control and Mechanical Properties

“…[1,4,5,26,33] The shear lag model based on the continuum approach assumes that all the load transfer from a matrix to a particle occurs via stresses acting on the interface between the two constituents, and the yield strength (YS) of the composite is in a linear relationship with the volume fraction of the reinforcing particles with a very modest increase, [32] This however hardly accounts for any dependence of the YS on the particle size or other microstructural variables (interparticle spacing, grain size, or dislocation density). Micromechanics, on the other hand, considers strengthening mechanisms in the microstructural scale such as quench hardening due to the thermally induced dislocations and Orowan strengthening resulting from interaction between dispersed particles and dislocations.…”

“…where M is the Taylor factor (=2.6 for Al [33] ), m Poisson ratio (=0.34 [35] ), k p the interparticle spacing that can be expressed in terms of the volume fraction of dispersed particles, V p and the mean particle size of d p as [40] k p ¼ 0:5d p 3p 2V p 1=2…”