Effect of ZrB2 particles on the microstructure and mechanical properties of hybrid (ZrB2 + Al3Zr)/AA5052 insitu composites (original) (raw)

Present study outlines the effect of ZrB 2 particles variation on the morphology and mechanical properties of (ZrB 2 þAl 3 Zr)/AA5052Al alloy composites. Composites with varying amount of ZrB 2 particles have been produced by direct melt reaction (DMR) technique. These composites have been characterized by X-ray diffractometer (XRD) and energy-dispersive spectroscopy (EDS) to confirm the presence of ZrB 2 and Al 3 Zr particles. Optical microscopy (OM) and scanning-electron microscopy (SEM) have been used to understand the morphology. To see the effect of ZrB 2 variation on mechanical properties, hardness and tensile properties have been evaluated. The XRD and EDS results confirm the successful formation of ZrB 2 particles in matrix of AA5052Al alloy. SEM and TEM studies exhibit that ZrB 2 particles are mostly in hexagonal and some rectangular shape while Al 3 Zr particles are in polyhedron and rectangular shapes. Most of ZrB 2 particles are within a size range of 10e190 nm. Interface region is free of any impurity. OM studies show grain refinement of AA5052Al alloy matrix with formation of second phase ZrB 2 particles. Tensile results indicate that the UTS and YS improve up to 3 vol.% of ZrB 2 but beyond this composition a decreasing trend is observed. The strength coefficient increases with increase in ZrB 2 particles up to 3 vol.% in the Al 3 Zr/Al alloy composites, whereas strain hardening decreases. While beyond 3 vol.% ZrB 2 particles in the Al 3 Zr/Al alloy composite, opposite trend is observed in strength coefficient and strain hardening. Percentage elongation also improves with 1vol.% ZrB 2 , but further addition of ZrB 2 shows an adverse effect. However, a continuous increasing trend has been observed in bulk hardness. Fracture studies show facets of Al 3 Zr particles and dimples of matrix, but with inclusion of ZrB 2 dimple size decreases. Increase in ZrB 2 leads to quasi cleavage fracture and debonding of ZrB 2 clusters.