Summary of Mechanical Properties

The mechanical properties of the covalent carbides are summarized in Table 8.6. The values are average values reported in the recent literature.Hl li 25  

Covalent carbides are strong materials especially at high temperature. However, like the transition-metal carbides and most other ceramics, they are intrinsically brittle (for discussion, see Sec. 4.3 of Ch. 4). Silicon 

The covalent carbides, like the transition-metal carbides, have the ability to deform plastically above the ductile-to-brittle transition temperature. Below that temperature, the carbides fail in a brittle manner while above they show ductile behavior and undergo plastic deformation 

Compound Vickers Hardness (GPa) Young s Modulus of Elasticity (GPa) Shear Modulus (GPa) Flexural Strength (MPa) 

It is significant that two of the hardest materials contain boron (cubic boron nitride and boron carbide), boron itself being a very hard material, 

It should be emphasized that the strength properties are difficult and expensive to measure due to the iack of diamond of the required test size and configuration. The data presently available show a material of considerable strength 2Uid rigidity. 

The mechanical properties of diamond are summarized in Tabie 11 The properties were measured on single-crystal diamond either naturai or produced by high pressure. For comparison purposes, the table includes the properties of a high-strength ceramic, namely alumina. 

The very fact that diamond is the hardest known material makes it difficult to measure its hardness since only another diamond can be used as an indenter. This may explain the wide variations in reported values which range from 5,700 to over 10,400 kg/mm.  

The hardness of diamond is compared with that of other hard materials in Fig.11.16. The test method is the Knoop hardness test which is considered the most accurate for crystalline materials. The hardness is also a function of the crystal orientation as shown in Table 11.7. 

The hardness of diamond can also be determined form the elastic coefficients as there is a linear relation between hardness and these coefficients. 

As an illustration of the results of the measurements just described, the mechanical properties for four unidirectionally reinforced composite materials, glass-epoxy, boron-epoxy, graphite-epoxy, and Kevlar 49 - 

Glass-Epoxy Boron-Epoxy Graphite-Epoxy Kevlar -Epoxy 

Now that the basic stiffnesses and strengths have been defined for the principal material coordinates, we can proceed to determine how an orthotropic lamina behaves under biaxial stress states in Section 2.9. There, we must combine the information in principal material coordinates in order to define the stiffness and strength of a lamina at arbitrary orientations under arbitrary biaxial stress states. 

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Fig. 2. Summary of mechanical properties of composites containing various fillers...

Summary of Mechanical Properties of Bone, Dentine [3], Hydroxyapatite [3], and CBPCs. 

Table 1 presented a summary of mechanical properties achieved in typical glass and glass-ceramic composites with dispersion reinforcement. The values for fracture strength (fr) and fracture toughness (Kic) quoted in Table 1 are consistently higherthan typical values for... 

TABLE 15.5 Summary of Mechanical Properties of Some Ceramics Used in Orthopedic Applications... 

The goals for a ligament prosthesis or augmentation device must be to provide the necessary mechanical stability to the joint without premature degradation or failure. Table 15.8 provides a summary of mechanical properties for a number of synthetic grafts in comparison with normal ACL tissue. 

Table 2.59 Summary of Mechanical Properties of A13 Aluminum-28 v/o Thornel-50 Composite (5)...

Table 2.69 Summary of Mechanical Properties of Composite (5) Zinc and Zinc-Graphite...

A summary of mechanical properties achieved with CNT/inorganic matrix composites, as reported in the literature, is presented in Table 1. 

Table 2 Summary of mechanical properties for SGFR nylon 6,6 composites... 

Summary of Mechanical Properties of U.S. Polymeric E-720E/7781 (ECDE- 1/0-550) Fiberglass Epoxy ... 

Table 8.4 Summary of mechanical properties for PP and composite samples as a function of nanotube concentration and fiber draw ratio...

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