Effect of nanodiamond particle sizes on damping properties of ZK60 magnesium matrix composites

The aim of the research is to ensure that the material has functional mechanical properties as well as high-damping value. The microstructure, elemental composition, second phase distribution and interface structure of the Mg-based composite with different particle sizes were characterized by Optical Microscope(OM), X-Ray Diffractometer(XRD), Scanning Electron Microscope(SEM), Transmission Electron Microscope(TEM) and Energy Dispersive Spectrometer (EDS). The mechanical and damping properties of the ZK60 magnesium matrix composites were investigated an Instron5982 universal tester and Dynamic Mechanical Analysis (DMA). The results indicate that nanodiamond(ND) can disperse well in the composites. The elastic modulus of composite can reach 9.9GPa after reinforcement phase being added. Under certain conditions,the damping value can reach beyond 2.5×10-1, which is 117% of other composite. High-temperature damping depends on grain boundary slip and interface slip. The interfacial damping depends on the difference in the incoherent interface and thermal expansion coefficient between the nanodiamond and ZK60 matrix to slip and improve the damping value.

Machining and corrosion studies on HfC reinforced ZE41 magnesium matrix composites

In this paper, Hafnium Carbide (HfC) reinforced ZE41 Magnesium Matrix Composites (MMCs) were prepared by using stir casting method. Using three different reinforcement percentages of HfC such as 5%, 10% and 15% by wt., ZE41-HfC MMCs were prepared. The mechanical characteristics of ZE41-HfC MMCs were evaluated by subjecting them to tensile and surface micro-hardness studies. Using X-Ray diffraction (XRD) studies, chemical compounds formed in the interfacial layer between HfC & ZE41 Mg was observed. Using optical microscopy (OM) and scanning electron microscopy (SEM), the surface modifications in the composites due to HfC addition was studied. Using electron backscatter diffraction analysis (EBSD), the changes in particle grain sizes and orientation of ZE41-HfC MMCs were studied. Energy Dispersive Spectroscopy (EDS) analysis was used to identify the variations in elemental composition of the prepared ZE41-HfC MMCs. ZE41-HfC MMCs were subjected to drilling studies for identifying the variations in cutting forces. Using electrochemical studies, the corrosion resistance of ZE41-HfC MMCs was observed. SEM images of corroded ZE41-HfC MMCs revealed micro cracks and dense pits near HfC agglomerated region.