Polyphase alloy

Polyphase Alloys. The two-phase alloys have a rather wide range of properties resulting from variations within the stmcture. If the second phase is distributed in critical depression, the hardness and strength are at a maximum and the ductility is at a moderate level. Tensile strength may be 415—825 MPa (60,000—120,000 psi) yield strength, 170—585 MPa (25,000—85,000 psi) and elongation, 10—40%. 

The effect of a second phase is demonstrated in the copper—aluminum system, where increasing aluminum concentration causes the alloy system to change to a polyphase alloy. By obtaining a fine dispersion of the phase, the yield strength is increased from 225 to 480 MPa (33,000—70,000 psi). 

Protons are not the sole species that can be incorporated into the lattices of different host materials. At the beginning of the 1960s, Boris N. Kabanov showed that during cathodic polarization of different metals in alkaline solutions, intercalation of atoms of the corresponding alkali metal is possible. As a result of such an electrochemical intercalation, either homogeneous alloys are formed (solid solutions) or heterogeneous polyphase systems, or even intermetallic compounds, are formed. 

Huggins RA., Polyphase Alloys as Rechargeable Electrodes in Advanced Battery Systems. J. Power Sources 1988 22 341-50. 

Huggins RA. Polyphase alloys as rechargeable electrodes in advanced battery systems. J Power Sources 1988 22 341-350. 

Both of these alloys are solid solutions, which occur when the constituents of the alloy are soluble in each other, like ethanol is soluble in water. Unlike ethanol and water, which are completely miscible, if too much tin is added to copper and too much carbon to iron, they will exceed their solubilities. The result is a polyphase alloy, with characteristics that are different from solid solutions. This book will skip polyphase alloys to focus on solid solutions and the important question they pose Why are the solid solutions called bronze and carbon steel stronger and harder than their constituents ... 

Polyphase alloy A nonhomogeneous alloy in which the constituents are not distributed evenly as they are in a solid solution. 

The Debye-Scherrer and other variations of the powder method are very widely used, especially in metallurgy. The powder method is, of course, the only method that can be employed when a single-crystal specimen is not available, and this is the case more often than not in metallurgical work. The method is especially suited for determining lattice parameters with high precision and for the identification of phases, whether they occur alone or in mixtures such as polyphase alloys, corrosion products, refractories, and rocks. These and other uses of the powder method will be fully described in later chapters. 

An Accelerated Methodology for the Evaluation of Critical Mechanical Properties of Polyphase Alloys... 

High density (HDPE), 52 Irregularities, 52 Linear low density (LLDPE), 52 Low density (LDPE), 52 Molecular weight, 52 Melt flow index, 53 Melting temperature, 51 Moisture absorption, 51 Polymeric forms, 52 Resistance to chemicals, 52 Resistance to oxidation, 52 Shrinkage, 54 Unsaturations, 54 a-transition, 51 P-transition, 51 y-transition, 51 Polyisocyanate, 79 Polylactic acid, 79, 91 Polymer alloys, 48 Polymer processing additives, 646 Polymer rheology, 619 Polymeric forms, 52 Polyphase PlOO, 451 polypropylene (PP), 2, 11 Polypropylene homopolymer, 70... 

The solids A and B may be metal atoms. Mixing them will give us monophasic - or polyphasic alloys or atoms of non-metals. It may also be molecules of organic compounds or polymers. Finally, there are solutions of complex mineral compounds. Thus, alkali feldspars constitute a solid solution between the potassium term orthoclase (SisAlOg) , and the sodium term albite (Si3A10s)Na, which is unstable at low temperature. 

We know that there are two main categories of metal alloys single-phase alloys which are sohd solutions of metals and polyphasic alloys, formed of mixtures of phases which ate, generally, themselves, solid solutions with different compositions. 

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