Hardness, mechanical properties

A fully automated microscale indentor known as the Nano Indentor is available from Nano Instmments (257—259). Used with the Berkovich diamond indentor, this system has load and displacement resolutions of 0.3 N and 0.16 nm, respectively. Multiple indentations can be made on one specimen with spatial accuracy of better than 200 nm using a computer controlled sample manipulation table. This allows spatial mapping of mechanical properties. Hardness and elastic modulus are typically measured (259,260) but time-dependent phenomena such as creep and adhesive strength can also be monitored. 

TPEs range in hardness from as low as 25 Shore A up to 82 Shore D (Chapter 5, MECHANICAL PROPERTY, Hardness). They span a temperature of —34 to 17TC (—29 to 350°F), dampen vibration, reduce noise, and absorb shock. However,... 

Tests for indention under load are performed basically like the ASTM measure the hardness of other materials, such as metals and ceramics. There are at least four popular hardness scales in use. Shore A and Shore D is for soft to relatively hard plastics and elastomers. Barcol is used from the mid-range of Shore D to above it as well as RPs. Rockwell M is used for very hard plastics (Chapter 5, MECHANICAL PROPERTY, Hardness),... 

For example, the mechanical properties—hardness and elastic modulus—of ORMOSIL can be tuned by varying the degree of alkylation and thus the fraction of six- and four-member siloxane rings in the organosilica matrix. This enables fine tuneability of parameters of crucial practical importance (Figure 4.2).2... 

Such transformations have been extensively studied in quenched steels, but they can also be found in nonferrous alloys, ceramics, minerals, and polymers. They have been studied mainly for technical reasons, since the transformed material often has useful mechanical properties (hard, stiff, high damping (internal friction), shape memory). Martensitic transformations can occur at rather low temperature ( 100 K) where diffusional jumps of atoms are definitely frozen, but also at much higher temperature. Since they occur without transport of matter, they are not of central interest to solid state kinetics. However, in view of the crystallographic as well as the elastic and even plastic implications, diffusionless transformations may inform us about the principles involved in the structural part of heterogeneous solid state reactions, and for this reason we will discuss them. 

The chemical analysis, mechanical properties, hardness and impact properties were determined and found to conform to the specifications of the German Grade 30 NiMoCr8 alloy steel suitable for use as a shaft. 

On contrary, You et al. [118] showed that LT-LiCo02 can be easily prepared by mechanical activation of the mixture of anhydrous Li202 and CoO, but the amount of contaminations was significantly higher due to mechanical properties (hardness) of initial reagents. 

In this study the mechanical properties, hardness and reduced elastic modulus, were determined using nanoindentation, as discussed in the previous section. Nanoindentation was used to plot the mechanical properties throughout the lesion in order to evaluate the changes in hardness and reduced elastic modulus in the various regions of the in vitro caries-like lesions. 

Figure 19.29 shows the comparative shielding efficiency data for various materials. Rubber filled with lead oxides comes very close in performance to lead and is superior to concrete and aluminum. Exposure of these shields to radiation causes degradation of mechanical properties (hardness, in particular, is increased) but it does not affect shielding efficiency. 

Fig. 15.—Variation in Mechanical Properties (Hardness and Shock) with Cold Work.

Mechanical properties hardness, compression, thermal expansion... 

It was previously shown that rapidly solidified Al-RE and Al-TM-RE alloys (RE is rare earth metal or yttrium, TM is transition metal) have amorphous structure in relatively wide range of compositions and alloying elements [1], Similarly to rare earth metals and Y, Sc belongs to the IIIB group of the Periodic Table of Elements, but we have found no data on the influence of Sc on the formation of amorphous structure in A1 alloys in the literature. On the other hand, Sc is known for a many-sided improving action on many crystalline A1 alloys [2], The aim of this work was to investigate the effect of Sc on the structure and mechanical properties (hardness) of rapidly solidified binary Al-Sc alloys as well as of Al-Ce-Sc and Al-Ni-Ce-Sc amorphous alloys. 

Mechanical properties. Hardness is the most common mechanical test. See Chapter 5, Mechanical Testing. Hardness testing, for instance, may be used to indicate whether fasteners in specific critical services are greater or less than the value required to avoid a premature failure. Mechanical tests other than hardness are destructive. If a destructive test is required to ensure compliance it is performed on a sample piece from the lot. Mechanical tests are time consuming and only used when required by the specification. 

Mechanical Properties. Hardness (e.g., for compliance with ASTM A193 grade B7M). 

The correlation of grain size of metal and size of carbon clusters with mechanical properties (hardness, friction, wear) of a-C H,Cu and a-C,(Cu,Zr) films have been investigated. 

Oxides have excellent stability, good mechanical properties (hardness, wear resistance, strength) and thermal properties and are generally available at a low cost. The most commonly used oxides are ... 

Using a nanoindentation technique, Shen et al. [150] studied the effects of clay concentrations on the mechanical properties (hardness, elastic modulus, and creep behavior) of exfoliated polyamide 6,6-clay nanocomposites. The results were discussed in conjnnction with those obtained by dynamic mechanical analysis and optical microscopy, and also conjunction with changes in morphology, crystallinity, and x-ray diffraction. 

The in-use performance and handling of agglomerated or tabletted products is often closely related to structure (e.g., porosity) and mechanical properties (hardness, yield stress, modulus, toughness, etc.). The compaction diagram is a useful method to measure the properties of granular materials as well as the characterization of bulk structures (e.g., tablets) formed by compaction. 

Mutual alloying and doping improve the mechanical properties. Hardness values of the TiC-VC system with carbon-to-metal ratios close to 0.84 obtained for various cooling rates in a floating-zone process indicated that the variation in hardness of pure VCo,84 obtained by chang-... 

Among non-oxide ceramics, aluminum nitride developed recently. Its mechanical properties (hardness, breaking strength) are modest, bnt its thermal conductivity is very high. This conductivity associated with high electrical resistance, good dielectric property and a coefficient of expansion close to that of silicon, which varies linearly with the temperature, make it an excellent material for substrates for power micro-electronics (Figure 7.12). 

As for the room temperature mechanical properties, hardness, fracture toughness and Young s modulus do not seem to be substantially dependent on the sintering additive. On the other hand, strength directly follows the microstructural features in terms of grain size, residual glassy pockets, amorphous grain boundaries, etc. 

---