Metals, mechanical properties table

The wide composition range results in an equally wide range of physical (Table ld.20) and mechanical properties (Table ld.21). The high rigidity and strength of these alloys as compared to that of the precious metal alloys make them suitable for the production of small prosthetic devices. 

Several other metals have been used for a variety of specialized implant applications. Tantalum has been subjected to animal implant studies and has been shown very biocompatible. Due to its poor mechanical properties (Table 38.9) and its high density (16.6 g/cm ) it is restricted to few applications such as wire sutures for plastic surgeons and neurosurgeons and a radioisotope for bladder tumors. 

More than half of the elements in the Periodic Table react with silicon to form one or more silicides. The refractory metal and noble metal silicides ate used in the electronics industry. Silicon and ferrosilicon alloys have a wide range of applications in the iron and steel industries where they are used as inoculants to give significantly improved mechanical properties. Ferrosilicon alloys are also used as deoxidizers and as an economical source of silicon for steel and iron. 

Properties. Pure thorium metal is a dense, bright silvery metal having a very high melting point. The metal exists in two allotropic modifications. Thorium is a reactive, soft, and ductile metal which tarnishes slowly on exposure to air (12). Having poor mechanical properties, the metal has no direct stmctural appHcations. A survey of the physical properties of thorium is summarized in Table 1. Thorium metal is diamagnetic at room temperature, but becomes superconducting below 1.3—1.4 K. 

The gating and riseting system for cast aluminum bron2e is extremely important and must be arranged to iatroduce the metal quietly at the lowest portion of the mold. The alloys shrink well hence the gating and riseting must be well adapted to the particular casting. See Table 12 for properties of these alloys. Alloys C 95300, C 95400, and C 95500 are heat-treatable for iacreased mechanical properties and the last two should be temper-aimealed if used ia a corrosive environment. 

It should be noted that a number of aluminum alloys are available (see Table 28-16). Many have improved mechanical properties over pure aluminum. The wrought heat-treatable aluminum alloys have tensile strengths of 90 to 228 MPa (13,000 to 33,000 Ibf/in ) as annealed when they are fuUy hardened, strengths can go as high as 572 MPa (83,000 Ibf/in"). However, aluminum alloys usually have lower corrosion resistance than the pure metal. The alclad alloys have been developed to overcome this snortcoming. Alclad consists of an aluminum layer metaUurgicaUy bonded to a core alloy. 

In case of copper also, the end lemperalurc is considered at I8.S C only. Although ihis metal can susiain much higher lemperature than this, without any adverse change in its mechanical properties, merely as a consideration to Table 32.3, and to safeguard other components, insulations and welded parts etc., used in the same circuit. 

As you can see from the tables in Chapter 1, few metals are used in their pure state -they nearly always have other elements added to them which turn them into alloys and give them better mechanical properties. The alloying elements will always dissolve in the basic metal to form solid solutions, although the solubility can vary between <0.01% and 100% depending on the combinations of elements we choose. As examples, the iron in a carbon steel can only dissolve 0.007% carbon at room temperature the copper in brass can dissolve more than 30% zinc and the copper-nickel system - the basis of the monels and the cupronickels - has complete solid solubility. 

Titanium, tantalum and zirconium are used for construction in process plants. The principal physical and mechanical properties of these three metals are given in the Table 3.34. 

The mechanical properties of titanium are greatly affected by small amounts of oxygen and nitrogen. The properties of the commercially pure grade metal and its alloys are given in the Table 3.35. 

The precious metals are many times the cost of the base metals and, therefore, are limited to specialized applications or to those in which process conditions are highly demanding (e.g., where conditions are too corrosive for base metals and temperatures too high for plastics where base metal contamination must be avoided, as in the food and pharmaceutical industries or where plastics cannot be used because of heat transfer requirements and for special applications such as bursting discs in pressure vessels). The physical and mechanical properties of precious metals and their alloys used in process plants are given in Table 3.38. 

Hydrogen-induced cracking (HlC) is most commonly encountered in steels but other metals are susceptible, as shown in Table 53.3. The presence of hydrogen atoms in a metal degrades some of its mechanical properties, especially its ductility, leading in some cases to embrittlement. 

Although in the majority of their applications the choice of noble metals is determined by their chemical rather than by their physical and mechanical properties, some consideration of the latter is necessary. The relevant information for the noble metals as a whole is given in Tables 6.1 and 6.2, and details relating to the individual metals will be found in the following paragraphs. 

Table 3-1 Examples of the mechanical properties of metal and plastic materials...

Table 3-1 gives typical mechanical property data for four materials, the exact values of which are unimportant for this discussion. Aluminum and mild steel have been used as representative metals and polypropylene (PP) and glass fiber-TS polyester reinforced plastics (GRP) as representative plastics. Higher-performance types could have been selected for both the metals and plastics, but those in this table offer a fair comparison for the explanation being presented. 

Molybdenum is a high-strength refractory metal, although recrystallizes above 950°C with accompanying reduction in mechanical properties. It is easily fabricated. Its properties are summarized in Table 6.6. CVD is commonly used for the production of molybdenum coatings and free-standing shapes. 

Properties. Properties of SiC fibers are shown in Table 19.2. They are similar to those of CVD boron fibers except that SiC is more refractory and less reactive than boron. CVD-SiC fibers retain much of their mechanical properties when exposed to high temperature in air up to 800°C for as long as one hour as shown in Fig. 19.3. [ 1 SiC reacts with some metals such as titanium in which case a diffusion barrier is applied to the fiber (see Sec. 2.5 below). 

Table 7.2. Mechanical properties of common metals and alloys (typical values at room temperature)...

Ferrous Alloys. Many ancient objects allegedly made of iron actually consist not of the pure metal but of alloys of iron and carbon known by the generic name ferrous alloys. These can be broadly classified into two classes steel and cast iron. Steel is the common name for iron-carbon alloys in which the relative amount of carbon ranges between 0.03% and 2%. If the relative amount of carbon in the alloy exceeds 2%, the alloy is known as cast iron (see Table 33) (Angus 1976 Wertime 1961). Steel is outstanding because of the mechanical properties that it acquires when subjected to heat treatment, which causes changes in its structure and physical properties (see Textbox... 

Due to the high densities of metals, the resulting classification (Table 1.7 and Figures 1.5 and 1.6) is different from that of the mechanical properties alone. 

As for the specific mechanical properties, the high densities of metals modify the classification (Table 1.11 and Figure 1.9) of the various materials. 

Likewise, the mechanical properties of the copolymers were nearly identical or even somewhat enhanced towards the polyimide homopolymer in terms of the modulus and tensile strength values [44,47]. For most of the block copolymers, the elongations to break were substantially higher than that of PMDA/ODA polyimide (Table 4). The shape of the polyimide stress-strain curve is similar to that of a work-hardened metal with no distinguishable yield point... 

In principle, one could consider a number of metals and alloys to be used for the construction of the magnet but, considering their physical and electrical characteristics, copper and silver are undoubtedly the best choices. This assertion sounds obvious but the use of other metals with higher resistivity, such as aluminum alloys, is sometimes justified because of their negligible cost and mechanical properties which simplify the manufacturing process. The most important physical characteristics of the best conductors such as OF copper (Oxygen Free) and silver, are shown in Table I. 

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