Study On Preparation Technology For SiCp/Al-Mg-Zn Composites

Lightweight is one of the most important factors which can upgrade our country's High-speed Railway.It is key points that reduce weight of drisk Brake using a new material.In the present work, a stirring cast meathod was used in hope of producing a new particulate reinforced Aluminium matrix composites.SiC particulate was selected as the reinforcement which have a average size of 20μm.The matrix alloy of the composite was Al-6Mg-3.5Zn.The main objective of this work is to reveal the mechanical stirring processing,the remelting and adjustable pressure vacuum casting process,the dry sliding wear behavior of SiCp-A16Mg3.5Zn cast composites.The microstructure of the produced composites was examined by optical microscope.A uniform distribution of SiCp within the matrix is achieved at 580℃and 900rpm.There was no particle clustering and oxide inclusion in matrix.The posority of composites reach 1.43%.From the SEM image, there was no interfacial reaction layer at the interface,the bond between particle and matrix was strong.The microstructural feature was in the form of dendrites.It seemed that large paicle were entrapped between primary dendritic arms,while comparatively small paticle were entrapped between the second arms.A 15wt%SiCp-AlMgZn tensile sample was produced by remelting and adjustable pressure vacuum casting process.The tensile strength can reached 393MPa and the elongation was reached 1.1%。Examination of the fracture behaviour of this composites, it is significant to note that paricle fracture was observed everywhere.There was also some decohesion in tensile fracture.The wear resistance of the alloy is improved due to paticle addition.The composites exhibited low wear loss than that of the matrix alloy.The coefficient of friction for composite is higher than that of matrix alloy.The coefficient of friction was almost constant with silding distance(1000-2000m) at applied pressure 50N. On worn surface of material formation of continuous grooves,MML and some damaged regions at lower applied pressures;Series of parallel transverse as well as longitudinal cracks and damaged portion,propagation of longitudinal and transverse cracks resulted in the formation of flaky shape debris and stability of MML found at mediun applied pressure. In seizure condition,the wear surface is characterized by the formation of delamination,tearing of surface material along the silding direction.This article had succeed prepration a new SiC particle reinforced Alunimiun composites.Processing parameter of stirring and remelting was confirmed.This work also studyed on the mechanical properties and friction performance of this composite. Some based research has been done on this composite which can provide the potential application in Disc Brake.