Structural composite materials tailored for damping

The carbon fabric composites filled with the particulates of polyfluo-150 wax (PFW), nano-particles of ZnO (nano-ZnO), and nano-particles of SiC (nano-SiC), respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and the successive curing. The friction and wear behaviors of the carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration are evaluated on a Xuanwu-III high-temperature friction and wear tester. The morphologies of the worn surfaces of the filled carbon fabric composites and the counterpart steel pins are analyzed by means of scanning electron microscopy. The effect of the fillers on the adhesion strength of the adhesive is evaluated using a DY35 universal materials tester. It is found that the fillers PFW, nano-ZnO, and nano-SiC contribute to significantly increasing anti-wear abilities of the carbon fabric composites, however, nano-SiC increase the friction coefficient of the carbon fabric composites. The wear rates of the composites at elevated temperature above 180 °C are much larger than that below 180 °C, which attribute to the degradation and decomposition of the adhesive resin at an excessively elevated temperature. That the interface bonding strength among the carbon fabric, the adhesive, and the particles is significantly increased after solidification and with the transferred film of the varied features largely account for the increased wear-resistance of the filled carbon fabric composites as compared with the unfilled one.

Study on the friction and wear properties of carbon fabric composites reinforced with micro- and nano-particles

Hybrid fiber reinforced composites using a nanoscale reinforcement of the interface have not reached their optimal performance in practical applications due to their complex design and the challenging assembly of their multiscale components. One promising approach to the fabrication of hybrid composites is the growth of zinc oxide (ZnO) nanowire arrays on the surface of carbon fibers to provide improved interfacial strength and out of plane reinforcement. However, this approach has been demonstrated mainly on fibers and thus still requires complex processing conditions. Here we demonstrate a simple approach to the fabrication of such composites through the growth of the nanowires on the fabric. The fabricated composites with nanostructured graded interphase not only exhibit remarkable damping enhancement but also stiffness improvement. It is demonstrated that these two extremely important properties of the composite can be controlled by tuning the morphology of the ZnO nanowires at the interface. Higher d...

Morphology-controlled ZnO nanowire arrays for tailored hybrid composites with high damping.

Nanowire-toughened transition layer to improve the oxidation resistance of SiC–MoSi2–ZrB2 coating for C/C composites

Fabrication of Al–Zn/α-Al2O3 nanocomposite by mechanical alloying

Reaction-processed Al-Cu/α-Al2O3 (p) composites, in which α-Al2O3 particles are distributed homogeneously, were fabricated via the chemical reactions between copper oxide (CuO) and aluminium. From the examination of the wear properties of the composites, it is proposed that the wear resistance of the composites is better than that of the corresponding matrix alloy, since α-Al2O3 particles play the main role in taking the external load and there is good interfacial cohesion between α-Al2O3 particles and the alloy matrix.

Study on reaction-processed Al–Cu/α-Al2O3 (p) composites

Damping characteristics of CVI-densified carbon–carbon composites

Internal friction behavior of carbon–carbon composites

The chemical reactions in the CuO/Al system were studied via scanning electron microscopy (SEM) and X-ray diffractometry. It is proposed that there are two main chemical reactions in the CuO/Al system, i.e. 6CuO+2Al=3Cu2O+Al2O3 and 3Cu2O+2Al=Al2O3+6Cu. The produced particles are 0.5–2.0 μm in size, which are believed suitable to be the reinforcement particles in aluminum (alloy) matrix composites.

On the chemical reactions to process particle reinforced Al–Cu alloy matrix composites

Internal friction directly depends on the microstructure of material. For carbon–carbon composites made up of fibers, matrix and interface, internal friction mechanisms involved are more complex. In present work, the effects of microstructure on the internal friction in carbon–carbon composites are studied. During the Chemical Vapor Infiltration (CVI) process, the internal friction in carbon–carbon composites decreases with the increasing of density. The experimental result does not accord with the equation for conventional composites. Considering the porous structure and non-full ideal interfacial adhesion in carbon–carbon composites, we develop a modified equation for the quantitative description of internal friction, which shows good agreement with the experimental results. Furthermore, internal friction related to pyrolytic carbon matrix, fibers and interface are discussed, respectively, which gives us a fundamental understanding on the internal friction in carbon–carbon composites. Among these internal friction mechanisms, interfacial internal friction is of special interest, as it causes some abnormal internal friction phenomena in carbon–carbon composites.

Zhengang Zhu

Papers

Study on reaction-processed Al–Cu/α-Al2O3 (p) composites

Damping characteristics of CVI-densified carbon–carbon composites

Internal friction behavior of carbon–carbon composites

On the chemical reactions to process particle reinforced Al–Cu alloy matrix composites

Effects of microstructure on the internal friction of carbon–carbon composites