Authors: ChangSoo Kim Il Sohn Marjan Nezafati J B Ferguson Benjamin F Schultz Zahra BajestaniGohari Pradeep K Rohatgi Kyu Cho
Publish Date: 2013/02/23
Volume: 48, Issue: 12, Pages: 4191-4204
Abstract
Particlereinforced metal matrix nanocomposites MMNCs have been lauded for their potentially superior mechanical properties such as modulus yield strength and ultimate tensile strength Though these materials have been synthesized using several modern solid or liquidphase processes the relationships between material types contents processing conditions and the resultant mechanical properties are not well understood In this paper we examine the yield strength of particlereinforced MMNCs by considering individual strengthening mechanism candidates and yield strength prediction models We first introduce several strengthening mechanisms that can account for increase in the yield strength in MMNC materials and address the features of currently available yield strength superposition methods We then apply these prediction models to the existing dataset of magnesium MMNCs Through a series of quantitative analyses it is demonstrated that grain refinement plays a significant role in determining the overall yield strength of most of the MMNCs developed to date Also it is found that the incorporation of the coefficient of thermal expansion mismatch and modulus mismatch strengthening mechanisms will considerably overestimate the experimental yield strength Finally it is shown that workhardening during postprocessing of MMNCs employed by many researchers is in part responsible for improvement to the yield strength of these materialsThis work is primarily supported by the Research Growth Initiative RGI Award from University of WisconsinMilwaukee UWM Partial support from the US Army Research Laboratory US ARL under Cooperative Agreement No W911NF0820014 is also acknowledged The views opinions and conclusions made in this document are those of the authors and should not be interpreted as representing the official policies either expressed or implied of Army Research Laboratory or the US Government The US Government is authorized to reproduce and distribute reprints for Government purposes notwithstanding any copyright notation herein
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