The Microstructure And Properties Of AlCrFeNi Multi-principal Element High Entropy Alloy Based Composites

Multi-principal element high-entropy alloys as a newly developed alloy system, breaks through the traditional alloy design frame work which is based on one major alloy element. In addition, it presents especial microstructure and novel properties. In this paper, we mainly studied the micro-structure and mechanical properties of AlCrFeNi multi-principle element alloys based composites.AlCrFeNi multi-principle element alloys based composites were prepared by NCAM. The microstructures and phase structures were systematacially investigated by OM, SEM, EDS, and XRD. Furthermore, the microhardness, compression properties were also tested and analyzed.The analysis shows that the phases of all multi-principle element alloys based composites in this study are simple BCC solid solution structure + reinforcement phase. The TiC reinforcement phase is usualy particals and embeded in the matrix alloy homogeneously And there also exist second-ordered TiC.By the addition of the reinforcement phase, the size of all the phase in the alloys are decreased The second-ordered TiC increased with the increasing of the cooling rate. In the AlCrFeNi-10vol%TiC composites, the size of TiC is larger.With the increasing of the cooling rate, the micro-hardness of the AlCrFeNi-TiC composites increases. AlCrFeNi-10vol%TiB₂ has the highest microhardness, and it reaches 775HV. AlCrFeNi-TiC and AlCrFeNi-5vol%TiB₂ has the best mechanical properties. And when it comes to AlCrFeNi-10vol%TiB₂, because of the formation of Laves phase, the mechanical properties decrease remarkably, as it brakes down directly after 8.2% of strain deformation. By the increase of the volume diffration of the enhencement phase,the strength and plastic of AlCrFeNi-TiC decrease, as the micro-structure around the enhence phase is affeceted by the later. And by the increase of the cooling rate, the mechanical of the composites increase. AlCrFeNi-TiC and AlCrFeNi-5vol%TiB₂, as river like pattern and concaves of the enhance phase can be observed on the fracture surface, are mainly cleavage fracture.