Aluminum Vickers hardness

FIGURE 10.13 Effect of aluminum content on Vickers hardness of 0.1% C steel. (From D.K. Hanink and A.L. Boegehold, Trans. SAE 61, 1953, 349. With permission.)... 

Figure 157. Vickers hardness of single-crystal ot-aluminum oxide as a function of load. Indentation face (0001). 1000 gf = 9.81 N.

Figure 2.11. The effect of surface preparation on the measured Vickers hardness of aluminum metal as a function of indent depth, (a) Emery paper polish, (b) Fine emery, 10 minutes, (c) Fine alumina polishing cloth, (d) Electropolished. (e) Annealed after polish.

The hardness of aluminum oxide is very high, as measured by Vickers hardness tester. High hardness shows that the material is less plastic. Only very high stresses can move the dislocations. One way of altering the dislocation mobility is by dissolving other oxides. The addition of iron oxide to alumina did not show much strengthening. When a solid solution was formed by the addition of chromia, the hardness of alumina was increased [13]. 

Nanoskiving forms intact stmctures from films of relatively soft and compliant metals (softer than platinum, or those with bulk values of hardness < 500 MPa, Vickers scale), while hard and stiff materials tend to fragment (those harder than irickel, or >500 MPa). The Whitesides laboratory has successfully formed nanostmctures of aluminum, copper, silver, gold, lead, bismuth, palladium, platinum, nickel, germanium, silicon dioxide, all conducting and semiconduaing polymers tested, and films of lead sulfide nanocrystals. ... 

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