Common Engineering Materials

The densities of common engineering materials are listed in Table 5.1 and shown in Fig. 5.12. These reflect the mass and diameter of the atoms that make them up and the efficiency with which they are packed to fill space. Metals, most of them, have high densities because the atoms are heavy and closely packed. Polymers are much less dense because the atoms of which they are made (C, H, O) are light, and because they generally adopt structures which are not close-packed. Ceramics - even the ones in which atoms are packed closely - are, on average, a little less dense then metals because most of them contain light atoms like O, N and C. Composites have densities which are simply an average of the materials of which they are made. 

Most common engineering materials are both homogeneous and isotropic ... 

Table 2 Typical Composition of Common Engineering Materials...

Corrosion of most common engineering materials at near-ambient temperatures occurs in aqueous (water-containing) environments and is electrochemical in nature. The aqueous environment is also referred to as the electrolyte, and, in the case of underground corrosion, it is moist soil. Corrosion is a common form of structure degradation that reduces both the static and cyclic strength of a pipeline. There is always the chance that pipelines could leak or rupture, and a pipeline failure can cause serious human, environmental, and financial losses [3-5]. 

One reason that polymers are such common engineering materials is that their properties can be tailored in a number of ways. The most obvious is the choice of the monomer unit because we know that different polymers can offer vastly different characteristics. But it is also possible to have distinctly different properties in polymers derived from the same monomer. One variable is the... 

Fortunately, many of the processes and tools that are satisfactory for working with metals, wood, and other common engineering materials also apply to plastics. Although there are similarities in these processes, there are also some critical differences that must be considered due to the unique nature of polymeric materials. The material properties of the pol3uneric resins will dictate the processing parameters that can be used. There are also certain unique assembly and finishing opportunities aveiilable for the designer because the material is a plastic. It... 

Table 2.2 Co-efficient of expansion of some common engineering materials...

The first materials used for making household utensils and ornamental objects included metals, such as gold, copper, and iron. Whereas gold was found in its pure state by early man, copper was most likely the first metal to be extracted successfully. The production of steel is said to have started about 600 to 800 CE. The periods that followed saw the development of a wide variety of ferrous and nonferrous metals. To date, there have been significant developments in engineering materials. Common engineering materials are now classified to include engineered materials, such as ceramics and reinforced composite materials, alloys of various types, and nanomaterials. 

The materials used to construct the SSR enclosure, SSR scaffolding, and SSR interior should be common engineering materials used by current fabrication technologies metals, alloys, plastics, ceramics, silicon or other special materials. The scale of these artifacts to be fabricated as elements of the artificial SSR must be selected with care as there are two opposing considerations which must be balanced and compromised. 

Graphite is one of the common engineering materials used in various applications from lubrication to micron-sized reinforcement for composite materials. Structurally, graphite is a layered material comprising Sp -bonded carbon atoms in a planar arrangement separated by an interlayer distance of 0.335 nm as shown in Figure 8.1 (Senguptaa et al., 2010). 

Fig.4 Tensile strength comparison of common engineering materials. Based on [24]...

This appendix compiles important properties for approximately 100 common engineering materials. Each table gives data values of one particular property for this chosen set of materials also included is a tabulation of the compositions of the various metal alloys that are considered (Table B.IO). Data are tabulated by material type (metals and metal alloys graphite, ceramics, and semiconducting materials polymers fiber materials and composites). Within each classification, the materials are listed alphabetically. 

Various reaction bonded composites with up to 70% by weight diamond were successfully produced and property measurements were successfully taken. Thermal conductivity was measured for these composites up to 447 W/m K. The coefficient of thermal expansion also approached 1 ppm/K as the diamond content was increased. The thermal stability as well as mechanic stability were also calculated and compared to common engineering materials. The diamond containing materials compared favorably with the common engineering materials charted. 

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