Hardness of metals

Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials Test Method for Vickers Hardness of Metallic Materials Test Method Microhardness of Materials... 

Test Method for Indentation Hardness of Rigid Plastics via Barcol Impresser Test Method for Indentation Hardness of Metal using Portable Hardness Testers Webster Hardness Gauge ... 

For sieve plates, thickness is usually in the lO-to-14 U.S. standard gauge range of 3.58 to 1.98 mm, or 0.141 to 0.078 in. Hardness of metal, size of die, and hmits on hole size (for process reasons) lead to the following thickness criterion ... 

Tabor, D., The Hardness of Metals. Clarendon Press, Oxford, 1951. 

Tabor, D. The hardness of Metals, Oxford C. Press, New York 1951... 

Allen GC, Warren KD (1974) The Electronic Spectra of the Hexafluoro Complexes of the Second and Third Transition Series. 19 105-165 Alonso JA, Baibas LC (1993) Hardness of Metallic Clusters. 80 229-258 Alonso JA, Baibas LC (1987) Simple Density Functional Theory of the Electronegativity and Other Related Properties of Atoms and Ions. 66 41-78 Andersson LA, Dawson JH (1991) EXAFS Spectroscopy of Heme-Containing Oxygenases and Peroxidases. 74 1-40 Antanaitis BC, see Doi K (1988) 70 1-26... 

Prut, E.V., Zelenetskii, A.N., Chepel, L.M., Erina, N.A., Dubnikova, I.L., and Novikov, D.D., Thermoplastic elastomer composition and the way of its manufacturing, Russian Patent 206927/B.I., 32, 1996. ASTM. Standard Test Method for Vickers Hardness of Metallic Materials, 1987. 

A dramatic change in the hardnesses of metallic materials occurred when the smelting of iron was invented in Egypt (4000 BCE). By 1550 BCE, it could be forged into wrought iron which considerably improved its properties. 

A measure of shear strength is the shear modulus. For covalent crystals this correlates quite well with hardness (Gilman, 1973). It also correlates with the hardnesses of metals (Pugh, 1954), as well as with ionic crystals (Chin, 1975). Chin has pointed out that the proportionality number (VHN/C44) depends on the bonding type. This parameter has become known as the Chin-Gilman parameter. 

Thus, in simple metals, interactions between dislocations rather than interactions between atoms, are most important. The hardnesses of metals depend on deformation hardening (dislocation interactions) rather than individual mobilities. The elastic resistance to shear plays a dominant role because it is directly involved with dislocation mobility. 

The hardnesses of metallic glasses vary with composition and temperature. The hardness is determined by the mobilities of dislocations in them (Gilman, 1968). 

Figure 14.6 Hardnesses of metallic glasses vs. their elastic shear moduli. Data from Davis et al., 1994. The glass compositions are Cu68Zr32, Fe4oNi38Mo4Bi8, FeB (various). The line in the graph has a slope of G/2jl...

Rockwell Rockwell Hardness and Rockwell Superficial Hardness of Metallic Materials E18... 

Vickers DPH Test Method for Vickers Hardness of Metallic Materials E92... 

Portable Test Method for Indentation Hardness of Metal using Portable Hardness Testers E110... 

Glazov V. M., Vigdorovich V. N., 1969, Tverdost metallov Hardness of Metals), Izd. Metallurgiya, Moskva. 

Kurnakov N. S., Zhemchuzhnyi S. F., 1908, Tverdost metallicheskikh tverdykh rast-vorov i opredelennykh khimicheskikh soedinenii (Hardness of Metallic solid solutions and specified chemical compounds), S. Pb. Polit. Inst. 9, 393. 

Even Democritus and Epicurus laying down the hypothesis of an atomic structure of bodies, associated hardness with the binding force of atoms. The first attempts at a theoretical interpretation of hardness on the basis of a mathematical analysis of the atomic structure of crystals date back to Bottone (1873), who analysing the interrelation of atomic weights, specific gravities and hardness of metal elements proposed the formula ... 

To calculate the hardness of metals, formula (3.5) takes a simpler form W2... 

BRINELL HARDNESS TEST. The standard method of measuring the hardness of metals. The smooth surface of the metal is dented by a steel hall under force. The standard load and time are 500 kg for 60 seconds for soft metals and 3000 kg for 30 seconds for steel and other hard metals. The size (diameter) of the resulting dent is measured, and the hardness determined from a chart or formula. 

The hardness of metallic chromium measured on Rydberg s system is 9-0, though pure chromium prepared by Moissan did not scratch... 

For about a century engineers and metallurgists have been measuring the hardness of metals as a means of assessing their general mechanical properties. How can one define the hardness of a material An interesting remark in this respect was made by O Neil (1967) in his introductory essay on the hardness of metals and alloys. He wisely pointed out that hardness, like the storminess of the seas, is easily appreciated but not readily measured . 

The methods most widely used in determining the hardness of metals are the static indentation methods. These involve the formation of a permanent indentation in the surface of the material under examination, the hardness being determined by the load and the size of the indentation formed. Because of the importance of indentation methods in hardness measurements a general discussion of the deformation and indentation of plastic materials is given in Chapter 2. 

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