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Volume fraction
About: Volume fraction is a research topic. Over the lifetime, 16312 publications have been published within this topic receiving 374181 citations.
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TL;DR: In this article, a detailed quantitative study on precipitation strengthening in AA6111, which is the alloy of choice in North America for exposed body panels, was performed using transmission electron microscopy to characterize the average size, the size distribution, the volume fraction, and the crystal structure of the hardening precipitates for aging at 180 °C.
Abstract: There is an increasing use of aluminum alloy sheet in automotive applications due to the desire to decrease vehicle weight. The current study provides a detailed quantitative study on precipitation strengthening in AA6111, which is the alloy of choice in North America for exposed body panels. Transmission electron microscopy was used to characterize the average size, the size distribution, the volume fraction, and the crystal structure of the hardening precipitates for aging at 180 °C (a) directly after solution treatment and (b) following 2 weeks of natural aging. The results indicate that both β″ and Q′ phases co-exist throughout the aging cycle with the relative amount of Q′ being increased both with increased aging time at 180 °C and when natural aging precedes aging at 180 °C. A strengthening model was developed which uses the size distribution and the volume fraction of precipitates as the primary inputs to predict the yield stress. An important feature of this model was that only one fitting parameter was necessary to give very good agreement with the experimental results.
119 citations
TL;DR: In this paper, the static coarsening behavior of the alpha-beta titanium alloy, Ti-6Al-4V, was established via a series of heat treatments at typical forging-preheat and final-heat treatment temperatures followed by quantitative metallography.
Abstract: The static-coarsening behavior of the alpha-beta titanium alloy, Ti-6Al-4V, was established via a series of heat treatments at typical forging-preheat and final-heat-treatment temperatures followed by quantitative metallography. For this purpose, samples of an ultra-fine-grain (UFG) size billet with a microstructure of equiaxed alpha in a beta matrix were heated at temperatures of 843 °C, 900 °C, 955 °C, and 982 °C for times between 0.25 and 144 hours followed by water quenching. The coarsening of the primary alpha particles was found to follow r
3-vs-time kinetics, typical of volume-diffusion-controlled behavior, at the three lower temperatures. At the highest temperature, the kinetics appeared to be fit equally well by an r
3 or r
4 dependence on time. The observations were interpreted in terms of the modified LSW theory considering the effect of volume fraction on kinetics and the fact that the phases are not terminal solid solutions. Prior models, which take into account the overall source/sink effects of all particles on each other, provided the best description of the observed dependence of coarsening on the volume fraction of primary alpha. In addition, the volume-diffusion kinetics derived for the UFG material were found to be capable of describing the coarsening behavior observed for industrial-scale billet of Ti-6Al-4V with a coarser starting equiaxed-alpha microstructure.
119 citations
TL;DR: In this paper, the thermal performance of an energy storage system filled with a porous medium and the void space inside the porous medium is occupied by a nano-PCM was investigated.
119 citations
TL;DR: In this paper, the authors showed that by decreasing the size of the barium titanyl oxalate nanoparticles coated with urea, achieved through Rb doping, the giant electrorheological (GER) effect can attain a yield stress of >250kPa.
Abstract: This letter shows that by decreasing the size of the barium titanyl oxalate nanoparticles coated with urea, achieved through Rb doping, the giant electrorheological (GER) effect can attain a yield stress of >250kPa. The shear thinning effect observed in parallel-plate sandwich configuration is also reported, and attributed to the centrifugal sedimentation effect of the inhomogeneous structures induced by applied electric field. In addition, it is found from experiments that the ER effect is very sensitive to the solid particles volume fraction.
119 citations
TL;DR: In this article, the effect of volume fraction and size distribution of reinforcement on wear and friction coefficient has been studied using Pin-on-Disc machine and it was observed that a heterogeneous tribo-layer was formed over the worn surfaces during the wear tests.
119 citations