1.2.3 Damage Analysis by Means of Scratch Test and 3D Optical Roughness Meter Wear testing quantifies the tribological behavior of the composites. Each wear test involved sliding a 2.5 mm diameter zirconia probe over a 1.5 to 2 mm long track at a frequency of 15 Hz under a load of 30 N for either 50,000 cycles or 100,000 cycles. The damage zone was investigated by a 3D optical-surface scanner. The resistance to scratch deformation (damage) was quantified in terms of scratch depth and wear volume. 1.2.4 Nanoindentation to Measure Constituent Properties Nanoindentation was used to measure the mechanical properties of the various constituents of EBAL 4. Nanoindentation was performed with an iNano fit with a Berkovich indenter (Nanomechanics, Inc., Oak Ridge, TN). EBAL 4 was tested with a new high-speed indentation technique in order to mechanically characterize all materials within a square area of 0.3 mm 0.3 mm; results are presented as highly resolved contour maps and spectra of properties. Within the selected area, an array of 60 60 indents was performed (a total of 3600 indents). Each indent had a peak load of 2mN and individual indents were separated by 5 microns. Indentations were performed at a rate of approximately 1 indent per second; thus, all 3600 indents were completed in about 1 h. 1.3 Results and Discussions 1.3.1 Dynamic Compression (Impact) Testing As mentioned earlier, reinforcing materials were incorporated into the epoxy matrix with the aim of improving its toughness. Figure 1.3 shows the impact force as a function of time for each composite. Further, the additional boron incorporated into Table 1.1 Composition of the epoxy-rubber based composites Epoxy-rubber based composition Reinforcements (wt%) Boron Alumina Glass bubbles EBAL 1 5 5 – EBAL 2 5 5 5 EBAL 3 10 5 5 EBAL 4 5 10 5 Fig. 1.1 Macrograph of the sample after compacting and post curing (a) d ¼50mm(b) d ¼30mm 1 Scrap-Rubber Based Composites Reinforced with Boron and Alumina 3
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