Strengthening mechanisms mechanism

Cao, G., Chen, X., Kysar, J.W., Lee, D., Gan, Y.X., 2007. The mean free path of dislocations in nanoparticle and nanorod reinforced metal composites and implication for strengthening mechanisms. Mechanics Research Communications 34, 275—282. 

A hardness indentation causes both elastic and plastic deformations which activate certain strengthening mechanisms in metals. Dislocations created by the deformation result in strain hardening of metals. Thus the indentation hardness test, which is a measure of resistance to deformation, is affected by the rate of strain hardening. 

Table 2. Strengthening Mechanisms in High Temperature Alloys...

Because pure aluminum is n picaUy too soft to be drawn into a fine wine, it is often alloyed with 1° o sihcon or 1° o magnesium to provide a sofid solution-strengthening mechanism. The resistance of Al-1° o Mg wine to fatigue failure and to degradation of ultimate strength after exposure to elevated temperatures is superior to that of Al—1° o Si wine. 

Dieter, G.E., Hardening Effect Produced with Shock Waves, in Strengthening Mechanisms in Solids, American Society of Metals, Metals Park, Ohio, 1962, pp. 279-340. 

E. V. Clougherty, D. Kalish, in Strengthening Mechanisms. Metals and Ceramics, Syracuse Univ. Press, Syracuse, 1966, p. 431. 

To strengthen mechanical properties and vary the transition temperature, hydrophobic monomers such as BMA were introduced into poly(IPAAm). The unique swelling properties with varying BMA composition are shown in Figure 11. 

Webb, W. W., H. D. Bartha, and T. B. Shaffer (1966). Strength eharacteristics of whisker crystals, macrocrystals and microcrystals, pp. 329-354. In Strengthening Mechanisms, Metals and Ceramics. Burke, J. J., N. L. Reed, and V. Weiss, Eds. Syracuse University Press, New York. 

TABLE 2. STRENGTHENING MECHANISMS IN HIGH TEMPERATURE ALLOYS... 

Other strengthening mechanisms include solid solution formation and strain hardening. Solid solution strengthening involves replacing a small number of atoms in the lattice with substitutional impurities of a slightly different size. This creates strain in the crystal. 

When a small amount (0.02%) of tetraethyllead, (C2H5)4Pb, is added to a mixture of methane and chlorine, chlorination takes place at only 140° instead of the usual minimum of 250°. In light of Problem 16, show how this fact strengthens the mechanism of Sec. 2.12. 

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