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The deformation characteristics of quenched and aged Ti-V alloys in the composition range 20 to 40 wt pct vanadium have been examined by optical metallography and transmission electron microscopy. A coarse lenticular deformation product similar in appearance to previously reported strain induced “martensites” was found to be associated with the occurrence of the omega phase. These features proved to be {112}〈111〉 twins. In the omega bearing alloys prolonged aging resulted in a transition of the deformation mode from twinning to slip at a point which corresponded either to the onset of embrittlement or alpha phase precipitation.

The strength characteristics and microstructures of aged Ni−Mo alloys containing ordered (Ni4Mo) precipitates were studied as a function of aging time and temperature. It was found that 17 at. pct Mo alloy aged at 750°C produced a uniform dispersion of cuboidal β precipitates which coarsened with time producing a gradual increase in flow stress. The flow stress increment was found to vary in qualitative agreement with both order strengthening and coherency strain models. Both these models give over-estimates of the strengthening increment. A negative dependence of flow stress on temperature is attributed to coherency strain contributions.

The influence of wire processing variables on the formation of subgrain structures and strengthening in three aluminum conductor materials is described. Electrical conductor grade aluminum, an Al-Fe-Mg alloy and an Al-Fe-Co alloy each develop subgrain structures with mean linear intercepts (•L) in the range of 0.4 to 1.5 μm with several sequences of wiredrawing and partial annealing. The yield strengths of these wires were found to obey a a = σ0 +k(•L) m relationship, with an exponentm = -1 independent of the processing sequence used to arrive at the structure. The role of precipitate particles in the alloys is to raisek above that for EC-A1 while Mg in solid solution increases σ0. The precipitates also affect the development of the substructure during the wiredrawing and annealing.

The structure and kinetics of aged Cu-15 Ni-8 Sn with and without prior deformation was investigated by means of X-ray diffraction and transmission electron microscopy. Deformation prior to aging is known to accelerate the hardening process in this alloy. The purpose of the study was to determine whether the strengthing mechanisms are kinetically enhanced through modified alloy decomposition or through other mechanisms. Deformation does not affect most of the features of structure development, including DO22 ordering in the tin-rich phase. However, for a given aging treatment, cold worked material shows a reduced strain modulation. The accelerated strengthening response in cold worked alloys cannot be attributed to an accelerated or altered decomposition process. It is suggested that the coarsened spinodal structure and the dislocation structure interact in a synergistic way to give the observed strengthening acceleration.

The microstructures and hardening characteristics of Al and Al with dilute additions of soluble and insoluble impurities were compared during wire drawing at room temperature to true strains (e w ) of 4.95. Three stages of microstructure change are observed: formation of a dislocation cell structure; cell boundary sharpening and cell size refinement; dynamic recrystallization. A minimum effective cell size is reached at an intermediate strain level corresponding approximately to the onset of dynamic recrystallization. The amounts and types of impurities at levels less than 1 pct have a great effect on the details of the microstructural changes as well as the hardening characteristics. 99.98 pct pure Al alternately saturates and hardens frome w = 0 to 4.95. Al-0.6 Fe (insoluble) work softens neare w = 3.5. Al-0.2 Mg (soluble) and EC Al (with 0.15 pct soluble and insoluble impurities) both work harden at a diminishing rate toe w ≃1.25 then enter a linear hardening stage which persists toe w ≃5. A linear relation between yield strength and inverse cell size is established for EC Al and Al-0.2 Mg in the cell refinement strain range; however, the Petch slope is much less than that of similar Al alloys subjected to elevated temperature dynamic or static recovery. Al-0.6 Fe does not exhibit a consistent linear relation between yield strength and inverse cell size. These differences can be attributed to the degree of recovery and the interrelation between cell size, cell boundary character and total dislocation density.

Age hardening and accompanying phase transformations were studied in a Cu-15Ni-8Sn alloy using mechanical testing, X-ray diffraction and microscopy techniques on samples aged at 300 to 550°C. At 450°C and below, strengthening is accompanied by the formation of sideband peaks about the fundamental reflections corresponding to a modulated structure with A≃ 100A. This structure is metastable and with further aging is displaced by a discontinuous (cellular) precipitation reaction which causes the yield strength to drop. A peak yield strength increment of ≃450 MPa is achieved in samples aged at 350°C. Both the hardening and the discontinuous transformation growth rates are increased by extensive deformation prior to aging. Prior deformation decreases the time to peak strength but does not significantly affect the peak strength increment. The early stages of aging correlate well with a spinodal strengthening model proposed by Ditchek and Schwartz which considers squaring of the composition modulation wave.