Structural Damages in Syntactic Metal Foams Caused by Monotone or Cyclic Compression

Closed cell, high strength metallic foams, like ceramic hollow spheres filled metal matrix foams are promising materials to build lightweight but high specific strength structural parts. The aim of this study is to investigate the damage of the foam structure during monotone or cyclic compression. The tested metal matrix syntactic foams were produced by inert gas pressure infiltration. Four different alloys as matrix and two different ceramic hollow spheres as filler material were applied. The cylindrical specimens were investigated in quasi-static and high strain rate compression and in cyclic compression. The higher strain rates were ensured by a Split-Hopkinson pressure bar system, while the fatigue tests were performed on a closed loop universal hydraulic testing machine. The failure modes of the foams have explicit differences showing barreling and shearing in the case of quasi-static and high strain rate compression respectively. In the case of the fatigue loading, there was a significant difference between the damage mechanisms of the unalloyed and the Si alloyed matrix syntactic foams. This can be explained by the difference between the yield strength of the matrix material and the ceramics hollow spheres.

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High strain rate compression of cenosphere-pure aluminum syntactic foams

Scripta Materialia ◽

10.1016/j.scriptamat.2007.07.024 ◽

2007 ◽

Vol 57 (10) ◽

pp. 945-948 ◽

Cited By ~ 71

Author(s):

Z.Y. Dou ◽

L.T. Jiang ◽

G.H. Wu ◽

Q. Zhang ◽

Z.Y. Xiu ◽

...

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

High Strain ◽

Pure Aluminum ◽

Syntactic Foams ◽

Strain Rate Compression

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Mechanical Behavior of Titanium Based Metal Matrix Composites Reinforced with TiC or TiB Particles under Quasi-Static and High Strain-Rate Compression

Materials ◽

10.3390/ma14226837 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6837

Author(s):

Pavlo E. Markovsky ◽

Jacek Janiszewski ◽

Oleksandr O. Stasyuk ◽

Vadim I. Bondarchuk ◽

Dmytro G. Savvakin ◽

...

Keyword(s):

High Strain Rate ◽

Strain Rate ◽

Mechanical Behavior ◽

Metal Matrix Composites ◽

Metal Matrix ◽

High Strain ◽

Strain Rates ◽

Matrix Composites ◽

Strain Rate Compression ◽

Static Conditions

The mechanical behavior of titanium alloys has been mostly studied in quasi-static conditions when the strain rate does not exceed 10 s−1, while the studies performed in dynamic settings specifically for Ti-based composites are limited. Such data are critical to prevent the “strength margin” approach, which is used to assure the part performance under dynamic conditions in the absence of relevant data. The purpose of this study was to obtain data on the mechanical behavior of Ti-based composites under dynamic condition. The Metal Matrix Composites (MMC) on the base of the alloy Ti-6Al-4V (wt.%) were made using Blended Elemental Powder Metallurgy with different amounts of reinforcing particles: 5, 10, and 20% of TiC or 5, 10% (vol.) of TiB. Composites were studied at high strain rate compression ~1–3·103·s−1 using the split Hopkinson pressure bar. Mechanical behavior was analyzed considering strain rate, phase composition, microstructure, and strain energy (SE). It is shown that for the strain rates up to 1920 s−1, the strength and SE of MMC with 5% TiC are substantially higher compared to particles free alloy. The particles TiC localize the plastic deformation at the micro level, and fracturing occurs mainly by crushing particles and their aggregates. TiB MMCs have a finer grain structure and different mechanical behavior. MMC with 5 and 10% TiB do not break down at strain rates up to almost 3000 s−1; and 10% MMC surpasses other materials in the SE at strain rates exceeding 2200 s−1. The deformation mechanism of MMCs was evaluated.

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