The Influence of Silicon Carbide Powders on the Enhancement of the Wear Resistance of Epoxy Resin

In order to improve wear properties of thermosetting resins, potential solutions are the reduction of the adhesion between the counterparts and the improvement of their hardness, stiffness and compressive strength. These goals can be achieved with success by using appropriate inorganic fillers. Concerning this, the present work shows the possibility to increase the abrasive wear resistance of an epoxy resin filled with hard powder. The filling is made by silicon carbide powders in different content and with different particle sizes. Abrasive tests, performed by means of a pin on disc apparatus, highlight that the wear of plain and reinforced resins increases both with the contact pressure between the counterparts and the counterface roughness. Moreover, the wear resistance of the filled resins increases with the increase of content and dimensions of the filling particles.

Advance Control of Vibration Mill with High Vibration Intensity Based on SCM(III) – Simulation Debugging and Test Comparison Analysis

An intelligent frequency advance control system based on Single-Chip-Microcomputer is developed. By simulation debugging of the system, existing problems is find, and the solutions to this problems are proposed so that improve the control system. Comparing with conventional vibration mill, the high vibration intensity(≥18) with certain frequency of the advance control system presents discontinuously, and super-high vibration intensity(≥20) presents several times. The result shows the advance control system can not only achieve the high vibration intensity with certain frequency, but also effectively control overrun and overtime of vibration intensity. The engineering effect of effective deaggregation and grain refinement in the super-hard powder superfine grinding is gained.

SYNTHESIS OF NANOSTRUCTURED GAMMA-TiAl BASED POWDERS AND BULK ALLOYS USING HIGH ENERGY MECHANICAL MILLING AND HIP

The microstructural evolution and powder particle morphology change in the process used to synthesize bulk nanostructured γ- TiAl intermetallic based binary Ti -47 Al (in at%) alloy (TA-1) and complex Ti -45 Al -2 Cr -2 Nb -1 B -0.5 Ta (in at%) alloy (TA-2) have been studied. This process combines high energy mechanical milling of elemental powder mixtures, thermal treatment and HIP. The bulk alloys consist of predominantly TiAl phase and a small fraction of Ti 3 Al phase, with the average grain sizes of the TiAl and Ti 3 Al phases being approximately 45nm and 40nm respectively in the bulk TA-1 alloy and being 37nm and 35nm respectively in the bulk TA-2 alloy. The study also shows that addition of a small fraction of hard powder particles such as Nb , Cr , B and Ta powder particles to the starting powder mixture has a significant effect in maintaining a small average particle size during high energy mechanical milling without using PCA and thus significantly enhances the mechanical alloying effect of the milling process.