Transactions of the Faraday Society, Том 12The Society., 1917 |
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acid alloys alumina aluminium amorphous analysis atomic volume Bauxite calorimeter carbon steels cent Chem chemical clay coarse coarse-grained composition compounds considerable cristobalite crucible crystalline crystals curve deformation determined diameter dolomite effect electric furnace equilibrium Faraday Society fire-clay firebrick fired fluxes ganister glass Glenboig grain-growth grain-size grog Hadfield Harker high temperatures important increase industry investigation Iron and Steel Laboratory lime liquid magnesite manufacture measurements melting-point metal metallurgical method microhms mineral mixture molecules National Physical Laboratory nozzle number of grains obtained occur oxide Paper physical properties practically pressure produced pure pyrometer quartz recrystallization reduction of area refractory materials retorts ROBERT HADFIELD samples sands Sheffield silica bricks SiO2 slag solid solution solvate specific heat specific resistance specimens strain structure surface tensile strength tests texture thermal conductivity tion Trans tridymite tube United States Pamphlet zirconia
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Стр. 60 - Aluminium which has been subjected to excessive cold work, shows an entire absence of structure, and has the appearance of a metal which has flowed and passed into a vitreous state. The reverse change takes place with extreme slowness and the ordinary annealing process does not change the structure from amorphous to crystalline. Aluminium annealed at a temperature of 500° C. for 10 hours appears to be " dead soft " and has its maximum elongation ; nevertheless it is still largely amorphous in structure...
Стр. 60 - C. for ten hours appears to be " dead soft," and has its maximum elongation ; nevertheless, it is still largely amorphous in structure when examined microscopically. Aluminium which has been annealed in this way without affecting the structure or only slightly altering it, hardens very rapidly when additional cold work is done upon the metal. The primitive crystals are transformed into the amorphous state much more readily than the larger crystals which are developed by annealing. The results of...
Стр. 174 - Reason progressive, instinct is complete ; Swift instinct leaps; slow reason feebly climbs. Brutes soon their zenith reach; their little all Flows in at once; in ages they no more Could know, or do, or covet, or enjoy. Were man to live coeval with the sun, The patriarch pupil would be learning still; Yet, dying, leave his lesson half unlearnt.
Стр. 43 - Heyn method1 depends for its accuracy on the assumption that the intercepts of a straight line intersecting a number of grains will be proportional to the square roots of the areas of the grains. In other words, the square of the average intercept will be the average area per grain. Heyn applies this assumption as shown in Fig. 3. The number of grains is counted along a line such as AB. The first incomplete grain is counted as one and the last grain is not counted. By taking a number of lines parallel...
Стр. 25 - ... tenacity and extensibility have high atomic volumes, while those which increase these properties have either the same atomic volume as gold or a lower one. The behaviour of aluminium and of lithium appeared to be somewhat exceptional. Gold contaminated with...
Стр. 46 - ... of the circle is occupied by the included grains. The following is an example of how the factor is used : Inclosed grains = 66.0 Boundary grains = 28.0 Factor = 0.6 66 + 0.6 X 28 = 82.8 grains within the circle. From the magnification, the number of grains per unit of area can be readily calculated. COMPARISON OF THE VARIOUS METHODS WITH THE PLANIMETER METHOD In making the calculations for the comparison of methods, the actual number of grains per unit of area was not figured, the number of grains...
Стр. 274 - The engineer (or purchaser), or his agreed representative, shall have access to the works of the maker at any reasonable time, and shall be at liberty to inspect the manufacture at any stage, and to reject any material which does not conform to the terms of this specification. Pieces may be selected for the...
Стр. 45 - The area of the circle (diameter 1.83 in.) is 2.635 sq. in. 1.9:2.635 = 37 :X X = 51.3 the equivalent number of whole grains within the circle. 51.3 — 37 = 14.3 the equivalent number of whole grains in the inside portions of the 22 boundary grains. -~^ = 0.65 average portion of each boundary grain within the circle. If this factor be determined on a large number of samples, it may be used on unknown samples to find the equivalent number of whole grains within a circular area. If we call this factor...
Стр. 60 - The amount of cold work which can be done upon aluminum is limited by the formation of the amorphous state. Microscopic examination of polished and etched specimens taken at various stages during cold working shows that the crystalline structure disappears at a very early stage in the working, and unless the metal is annealed it will become fatigued, developing a species of
Стр. 49 - ... means of a free-hand sketch. 5. In samples which have been cold worked, the relative degree of cold work in any direction is expressed by the ratio of the length divided by the width of the grains. For obtaining this ratio, it is recommended that Heyn's method be used. APPARATUS AND MANIPULATION FOR GRAIN-SIZE MEASUREMENTS Any good metallurgical microscope with camera attachment can be used for grain-size determinations. It is recommended that only even magnifications be used. For instance, if...