Aluminum-titanium composites

Bouix, J., Vincent, H., Boubehira, M., and Viala, J. C., Titanium Diboride-Coated Boron Fibre for Aluminum Matrix Composites, J. Less Common Metals, 117(l-2) 83-89 (Mar. 1986)... 

Adhesives and sealers can be an important part of a total corrosion protection system. Structural bonding procedures and adhesives for aluminum, polymer composites, and titanium are well established in the aerospace industry. Structural bonding of steel is gaining increasing prominence in the appliance and automotive industries. The durability of adhesive bonds has been discussed by a number of authors (see, e.g., 85). The effects of aggressive environments on adhesive bonds are of particular concern. Minford ( ) has presented a comparative evaluation of aluminum joints in salt water exposure Smith ( ) has discussed steel-epoxy bond endurance under hydrothermal stress Drain et al. (8 ) and Dodiuk et al. (8 ) have presented results on the effects of water on performance of various adhesive/substrate combinations. In this volume, the durability of adhesive bonds in the presence of water and in corrosive environments is discussed by Matienzo et al., Gosselin, and Holubka et al. The effects of aggressive environments on adhesively bonded steel structures have a number of features in common with their effects on coated steel, but the mechanical requirements placed on adhesive bonds add an additional level of complication. 

Metals such as aluminium, steel, and titanium are the primary adherends used for adhesively bonded structure. They are never bonded directly to a polymeric adhesive, however. A protective oxide, either naturally occurring or created on the metal surface either through a chemical etching or anodization technique is provided for corrosion protection. The resultant oxide has a morphology distinct from the bulk and a surface chemistry dependent on the conditions used to form the oxide 39). Studies on various aluminum alloy compositions show that while the oxide composition is invariant with bulk composition, the oxide surface contains chemical species that are characteristic of the base alloy and the anodization bath40 42). 

The present research report deals with the preparation of egg-shell catalysts with controlled oxidic structure on metallic substrates like aluminum, titanium and magnesium. The influence of the substrate, electrolyte composition, and treatment time on the manufacture of egg-shell catalysts with tailor-made properties for the effective oxydehydrogenation of cyclohexane to cyclohexene will be presented. The selectivity control by the pore length is discussed. 

Polycrystalline diamond has been used for aluminum-matrix composites reinforced with particulate silicon carbide, boron carbide, or alumina. It also shows promise as a tool material for welding titanium, although this work is only in a preliminary stage. 

Boron/tungsten fiber applications include the use of filaments and of boron/tungsten fiber reinforced prepreg tape, aluminum matrix composites, and boron/graphite structures. The major applications for these structures are found in the aerospace market and about 25% in sporting goods markets [36]. SiC/carbon fiber reinforced products include aluminum, titanium, and ceramic matrix composites. Major applications for these structures are also found in the aerospace market, minor uses in the industrial market [37]. 

I Carbon composite I Aluminum Aramid composite SPFDB titanium... 

Metal-Ceramic Composites. Metals such as aluminum, titanium, copper and the intermetallic titanium aluminide, which are reinforced with silicon-carbide fibers or whiskers show an appreciable increase in mechanical properties particularly at elevated temperatures. These composites are being considered for advanced aerospace structures.1 1... 

Description and General Properties. Metal matrix composites (MMCs) consist of a metal or an alloy matrix with a reinforcement material (e.g., particulates, monofilaments, or whiskers). The matrix alloy, the reinforcement material, the volume and shape of the reinforcement, the location of the reinforcement, and the fabrication method can all be varied to achieve required properties. Most of the metal-matrix composites are made of an aluminum matrix. But aluminum-matrix composites must not be considered as a single material but as a family of materials whose stiffness, strength, density, and thermal and electrical properties can be tailored. Moreover a growing number of applications require improved matrix properties and therefore, metal matrices of magnesium, titanium, superalloys, copper, or even iron are now available commercially. Compared to bulk metals and their alloys, MMCs offer a number of advantages such as ... 

Figure 6-38. Tensile strengths and specific moduli of elasticity of different types of composite plastics including whisker fibers, as compared to aluminum, titanium, and steel.

In this chapter, we have described surface treatments for aluminum, titanium, and steel adherends. We have chosen to describe a few preparations for each metal in detail rather than present a comprehensive list of pretreatments for each. The rationale for this approach is that much is known about the morpology and composition resulting from each treatment and, more importantly, the roles of morphology and composition in bond durability have been investigated. 

The aims of the addition of inert ceramic filler to the electrospun polymer fiber matrix to form polymer/ceramic composite fiber membrane for separator in LIB were on one hand to prevent dimensional changes by thermal deformation at high temperature because of the frame structure of the heat-resistant ceramic powder and on the other hand to increase the ionic conductivity of the membrane due to the intrinsic ionic conductivity of the ceramics. Various ceramic fillers had been incorporated into the electrospun polymer membranes to make composite separators, including aluminum oxide (AI2O3) [61], fumed silica (SiOa) [29,48,62], titanium dioxide (Ti02) [50, 63-65], lithium lanthanum titanate oxide (LLTO) [51], and lithium aluminum titanium phosphate (LATP) [52],... 

As a result, ultra high modulus carbon fibers are preferred to others for their high stiffness/ density ratio for a low CTE compared with titanium or aluminum. Since composites are preferred to metal parts, bonding becomes the mandatory technology for fastening parts, because drilling and the bolt/nut/rivet principle require holes which affect the mechanical properties of the joint due to concentrations of loads around sectioned fibers. 

Although aircraft structures comprise thousands of components produced from a myriad of basic materials, the most common substrates for structural adhesive bonding are wood, aluminum, titanium, stainless steel, and the composite materials such as bonded sandwich structures, fiber-reinforced plastic (FRP) laminates, and fiber—metal laminates (FML) in which the metal is usually aluminum. 

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