The role of aging on the mechanical and microstructural response of aluminum 6061 to one-dimensional shock loading

Abstract

Articles you may be interested inLateral stress and shear strength behind the shock front in three face centered cubic metals J. Appl. Phys. 105, 033515 (2009); 10.1063/1.3077206 The response of the intermetallic compound Ni 3 Al to one-dimensional shock loading Compressive strength measurements in aluminum for shock compression over the stress range of 4 -22 GPa J. Appl. Phys. 98, 033524 (2005); 10.1063/1.2001729 Shock induced mechanical response of a γ-TiAl alloyThe shock response of the aluminum alloy 6061, and its variation according to heat treatment have been monitored via the placement of stress gauges in such orientations so as to be sensitive to the lateral component of stress, and hence the shear strength. To complement these measurements, the postshock microstructure and mechanical response have also been determined via full one-dimensional recovery techniques. Results have shown that the solution treated ͑T0͒ state, as a largely single phase material displays a fast rising shock pulse with a significant degree of hardening behind the shock front. This indicates that a high degree of dislocation generation is expected. Postshock analysis of recovered samples has confirmed this hypothesis, with dislocation cells being observed and a notable increase in the yield strength in comparison to the as-received material. In contrast, the aged ͑T6͒ experiments showed a much longer rise time with a lower degree of hardening behind the shock front. Microstructural analysis postshock shows a more randomized dislocation distribution, with little or no postshock hardening occurring once the shock induced strain has been accounted for. This has been attributed to the presence of fine Mg 2 Si precipitates inhibiting the motion and generation of dislocations. These measurements are in agreement with work previously carried out on this material. Comparison of the shear strengths of the two heat treatments also shows that although the T6 condition is a little higher than T0, the differences are somewhat lower than expected.

The Mechanical Response of Pre-Shocked Aluminium Single Crystals

“…Taking a wider look at fcc metals in general, post shock hardening can be effected by a number of factors. Significant levels of post shock hardening are seen in metals with moderate to high SFEs, such as copper [16], nickel [8] or aluminium alloys [17,18] (78, 128 and 166 mJ m -2 respectively [19]), but if the SFE is reduced by alloying, such as copper-aluminium alloys [20][21][22], or austenitic stainless steels [23], post shock hardening can be reduced to zero or even induce a reduction in post shock strength. This is explained in terms of the separation of partial dislocations; the lower the SFE, the wider the partial spacing, and the lower their mobility and ability to overcome obstacles by climb or cross slip.…”

“…This can often promote deformation by twinning, hence reducing the dependence on dislocation based deformation further. Alternatively, hardening can also be reduced by changing the microstructure in the same material, for example in the aluminium alloy 6061, where post shock hardening is significant in the solution treated, single phase state, it reduces to near zero when the material receives an aging treatment [18] that creates a distribution of nano sized Mg 2 Si particles throughout the microstructure that act as an impediment to dislocation motion. Therefore, as a global statement, reducing the dislocation mobility in polycrystalline fcc metals and alloys reduces the level of post shock hardening.…”

Intelligent Detector of Internal Combustion Engine Cylinder Pressure and Sensitivity Temperature Coefficient Compensation

“…There are three internal defects of mechanical pressure gauges [3,4]. They are mechanical hysteresis, stagnation or creeping, and elastic effect.…”

Modifications of the Response of Materials to Shock Loading by Age Hardening

“…In a series of articles, the effects of age hardening on the aluminum alloy 6061 [26] and a copper-2 wt pct beryllium alloy [27] have been investigated. It is the intention of this article to bring the reported results together such that greater insights into the effects of age hardening on the shock response of materials can be gained.…”