Volume 09 - Metallography and Microstructures Part 10 pot

Fig. 10 AZ31 B-F extrusion. Longitudinal view of hot- worked structure. Large, equiaxed recrystallized grains; particles of manganese-aluminum compound and fragmented Mg 17 Al 12 . Etchant 8, Table 1. 250× Fig. 11 AZ61A-F extrusion. Longitudinal view of hot-worked structure. Small, equiaxed recry stallized grains; stringers of fragmented Mg 17 Al 12 . See also Fig. 12. Etchant 6, Table 1. 250× Fig. 12 Same as Fig. 11 , except this specimen has not been etched, making the stringers of fragmented Mg 17 Al 12 more easily visible. As-polished. 250× Fig. 13 AZ80A-F extrusion. Longitudinal view of hot-worked structure. Small, equiaxed recrystallized grains; small amount of Mg 17 Al 12 discontinuous precipitate at the grain boundaries. See also Fig. 14. Etchant 3, Table 1 , 15 s. 250× Fig. 14 AZ80A-T5 extrusion. Longitudinal view showing much mottled Mg 17 Al 12 discontinuous precipitate near the grain boundaries, resulting from the artificial aging treatment. Compare with Fig. 13. Etchant 2, Table 1 , 5 s. 250× Fig. 15 ZK21A-F extrusion. Longitudinal view of hot- worked structure. Small equiaxed recrystallized grains at the boundaries of and also within large, unrecrystallized elongated grains. Etchant 6, Table 1. 100× Fig. 16 ZK60A-F extrusion. Longitudinal view of banded hot- worked structure. Small, recrystallized grains; light islands are solid solution deficient in zin c and zirconium (due to alloy segregation) and so more resistant to hot working. See also Fig. 17. Etchant 6, Table 1, then Etchant 4, Table 1. 250× Fig. 17 Same as Fig. 16 , except artificially aged to the T5 temper. Despite higher magnification, structure appears same as Fig. 16 (precipitate formed during aging is unresolvable by microscopy). Etchant 7, Table 1 , 7 s, then Etchant 6, Table 1, 1 s. 500× Fig. 18 HM31A-T5 extrusion. Longitudinal view of banded hot- worked structure. Small, recrystallized grains; dark Mg 4 Th grain-boundary precipitate; light islands are solid sol ution rich in thorium and so more resistant to hot working; gray particle is manganese. Etchant 5, Table 1. 500× Fig. 19 AZ80A-T5 forging. Longitudinal view of hot- worked structure, showing large, recrystallized grains and spheroidized Mg 17 Al 12 discontinuous precipitate mainly in the grains near the boundaries. Etchant 5, Table 1 . 200× Fig. 20 ZK60A-T5 forging. Longitudinal view. Structure same as Fig. 17 , but with slightly larger grains and increased alloy segregation. Etchant 7, Table 1, 7 s, then Etchant 6, Table 1, 2 s. 500× Fig. 21 HM21A-T5 forging. Longitudinal view. Structure is similar to that of sheet shown in Fig. 6 , except the forging has smaller grains. (Grain growth in sheet caused by solution heat treatment.) Etchant 5, Table 1. 250× Fig. 22 AM60A-F die casting. Small, cored grains of magnesium solid solution in which the aluminum content increases toward the boundaries; passive Mg 17 Al 12 compound at grain boundaries. Relief polishing causes dark areas. See also Fig. 23. Etchant 3, Table 1. 500× Fig. 23 AS41A-F die casting. Same structure as that shown in Fig. 22, but with the addition of Mg 2 Si in Chinese script and globular forms. Etchant 3, Table 1, 5 s. 500× Fig. 24 K1A- F die casting. Small crystals of zirconium randomly dispersed in grains of magnesium that are larger than those in more highly alloyed die castings (compare with Fig. 22, 23, and 25.) Etchant 2, Table 1 , 10 s. 250× Fig. 25 AZ91A-F die casting. Massive Mg 17 Al 12 compound at the boundaries of small, cored grains. Segregation (coring) in the grains and absence of precipitated discontinuous Mg 17 Al 12 are results of the rapid cooling rate of die castings. See also Fig. 26 and 27. Etchant 2, Table 1, 5 s. 500× Fig. 26 AZ92A-F permanent mold casting. Mg 17 Al 12 compound: massive (outlined) at grain boundaries; precipitated (dark) near grain boundaries. Slower cooling rate than that of die castings has resulted in larger grains than in structure shown in Fig. 25. Etchant 2, Table 1, 5 s. 250× Fig. 27 AZ92A-F sand casting. Same microstructure as that shown in Fig. 26, except the slower cooling rate, in comparison with that of permanent mold castings, has resulted in larger grains. See Fig. 32 for effects of aging. Etchant 2, Table 1, 5 s. 250× Fig. 28 AZ92A- F sand casting. The appearance of the interdendritic eutectic, a mixture of magnesium solid solution and Mg 17 Al 12 , was retained in this form by a rapid quench from above the eutectic temperature. See also Fig. 29. Etchant 2, Table 1, 5 s. 1500× Fig. 29 AM100A-F, as-cast. Massive Mg 17 Al 12 compound containing globul ar magnesium solid solution and surrounded by lamellar Mg 17 Al 12 precipitate. Normal air cooling produces this type of segregated eutectic. Compare with Fig. 28 and 30. Etchant 2, Table 1, 5 s. 500× Fig. 30 AZ92A-F, as-cast. Massive Mg 17 Al 12 compound surrounded by lamellar Mg 17 Al 12 precipitate. Normal air cooling of zinc-containing magnesium- aluminum alloys produces this type of completely divorced eutectic. Compare with Fig. 29. Etchant 2, Table 1. 500× Fig. 31 Massive Mg 32 (Al,Zn) 49 (white) in as-cast alloy AZ63A- F. Specimen etched with 50% picral to protect Mg 2 Si (hexagonal particle) from HF, then with 5% HF to blacken Mg 17 Al 12 and distinguish it from Mg 32 (Al,Zn) 49 , then with 10% picral to darken the matrix. 500× Fig. 32 Alloy AZ92A-T6 sand casting. Lamellar Mg 17 Al 12 precipitate (light and dark gray) was produced throughout the grains of magnesium solid solution by artificial aging. Some isolated islands of Mg 2 Si (white) are also present. Etchant 2, Table 1. 100× Fig. 33 Alloy AZ63A-T6 sand casting. Lamellar Mg 32 (Al,Zn) 49 discontinuous precipitate (dark) near some grain boundaries; some particles of Mg 2 Si and manganese- aluminum compounds. Note that with 6% Al there is less precipitate than with 9% Al (compare with Fig. 32). Etchant 2, Table 1, 5s. 250× Fig. 34 EZ33A-T5 sand casting. Interdendritic network of massive Mg 9 R compound. The precipitate in the dendritic grains of magnesium solid solution is not visible. Etchant 2, Table 1. 100× Fig. 35 ZK51A-T5 sand casting. Fine, degenerate eutectic magnesium- zinc compound at the grain boundaries. The grains of magnesium solid solution are essentially homogeneous. Etchant 2, Table 1, 5 s. 250× Fig. 36 ZH62A-T5 sand casting. Characteristic lamellar, or filigree, form of eutectic magnesium-thorium- zinc compound at the boundaries of grains of magnesium solid solution. 2% nital. 250× Fig. 37 QE22A-T6 sand casting. Massive Mg 9 R compound is present at the boundaries of grains of magnesium solid solution, resulting from partial solution and coalescence of the magnesium-didymium eutectic. Etchant 2, Table 1. 100× Fig. 38 HK31A-T6 sand casting. Intergranular particles of massive Mg 4 Th compound (gray, outlined). The precipitate in the grains of magnesium solid solution is not visible. See Fig. 39 for effect of zinc addition. Etchant 2, Table 1, 15 s. 500× Fig. 39 HZ32A-T5 sand casting. Intergranular Mg- Th compounds: bunches of acicular compound (dark gray) and small areas of massive Mg 4 Th (see Fig. 38). The precipitate within matrix grains is not visible. 2% nital. 250× [...]... compositions of nickel and nickel-copper alloys Alloy Composition Nickel 200 99.5Ni-0.08C-0.18Mn-0.20Fe Nickel 270 99.98Ni-0.01C Permanickel 300 98.5Ni-0.20C-0.25Mn-0.30Fe-0.35Mg-0.40Ti Duranickel 301 96.5Ni-0.15C-0.25Mn-0.30Fe-0.63Ti-4.38Al Monel 400 66.5Ni-31.5Cu-0.15C-1.0Mn-1.25Fe Monel R-405 66.5Ni-31.5Cu-0.15C-1.0Mn-1.25Fe-0.043S Monel K-500 66.5Ni-29.5Cu-0.13C-0.75Mn-1.0Fe-0.60Ti-2.73Al The microstructure... and continuously stirred Table 1 Electrolytes and current densities for electropolishing of nickel and nickel-copper alloys Electrolyte composition Applicable alloys Current density A/cm2 Nickel 200 1. 4-1 .5 9-1 0 Nickel 270 1. 5-1 .8 1 0-1 2 Duranickel 301 1.2 5-1 .5 8-1 0 Monel 400 37 mL H3PO4 (conc), 56 mL glycerol, 7 mL H2O A/in.2 0. 9-1 6-7 Etching The solutions and conditions for etching nickel alloys for... 2 FS-80 niobium alloy tube 3.2-mm ( 1 -in.) OD, 0.25-mm (0. 01 0- in.) wall (after 70% reduction), vacuum 8 annealed 1 h at 1150 °C ( 2100 °F) Longitudinal section Solid-solution matrix consists of large recrystallized grains (ASTM No 5- 1 ) Intragranular precipitate is probably ZrO2 30 mL each 50% HF, H2SO4, and H2O with 3 2 to 5 drops 30% H2O2 250× Fig 3 FS-85 niobium alloy (Nb-28Ta-11W-0.8Zr), 2.8-mm... nickel and nickel-copper alloys for grain boundaries and general structure Composition of etchant Conditions for use Etchants for Nickel 200 and 270; Permanickel; Duranickel 301; and Monel 400, R-450, and K-500 1 part 10% aqueous solution of NaCN (sodium cyanide), 1 part 10% aqueous solution of (NH4)2S2O8 (ammonium persulfate) Mix solutions when ready to use Immerse or swab specimen for 5-9 0 s(a) 1 part. .. molybdenum and tungsten Alternate Preparation Procedures for Niobium and Tantalum Polishing A typical method of rough polishing mobium and tantalum uses a wax wheel and 1 5- m levigated Al2O3 Intermediate polishing is performed using a synthetic rayon cloth-covered wheel and 1- m Al2O3; final polishing, a synthetic rayon cloth-covered wheel and 0. 3- m Al2O3 Polish-etching, also known as chemical-mechanical... annealed, and gas nitrided Scanning electron micrograph of titanium-rich nitride phase (dark) in a titanium-depleted niobium alloy matrix Outer surface of specimen is shown at bottom of micrograph 33% HCl and 17% HF in glycerol 500× Fig 7 Fig 8 Nb-46.5Ti, 13-mm (0.5-in.) diam rod Vacuum-arc melted into 2700-kg (6000-lb) ingot, press forged, rotary forged to 150-mm (6-in.) diam, annealed, and water... metallographic specimens and the microstructures of alloys containing 96% or more nickel (Nickel 200, Nickel 270, and Duranickel 301) and nickel-copper alloys (Monel 400, Monel R-405, and Monel K-500) are considered in this article Micrographs of these alloys are shown in Fig 1 to 15 in the section Atlas of Microstructures for Nickel and Nickel-Copper Alloys in this article The procedures and materials for... vapor) and by less Mg9R at grain boundaries than normal Etchant 3, Table 1 500× Fig 46 Segregation of zinc-zirconium-iron compound in a ZK61A-F sand casting This compound and Zr2Zn3 form under similar conditions; the two can be distinguished by etching with 10% HF, which attacks Zr2Zn3 but not zinc-zirconium-iron Etchant 2, Table 1, 10 s 250× Fig 47 Segregation of layered oxide skin in a ZK61A-F sand... 2.8-mm (0. 11 0- in.) thick sheet Arc melted, hot extruded, warm rolled at 705 °C (1300 °F), 50 to 75% reductions between anneals Final anneal in vacuum at 1315 °C (2400 °F) for 1 h Longitudinal section of fully recrystallized structure showing typical banding ASTM grain size 7 Etchant: ASTM 163 250× Fig 4 C -1 03 niobium alloy (Nb-10Hf-1Ti-0.5Zr), 6.4-mm (0.25-in.) thick plate, cold worked and annealed... °F) and quenched in water Nickel-copper solid-solution matrix See also Fig 11, 12, 13, 14, and 15 NaCN, (NH4)2S2O8 100 × Fig 11 Same as Fig 10, but at higher magnification Portions of only three grains are visible The black dots are nitride particles See also Fig 10, 12, 13, 14, and 15 NaCN, (NH4)2S2O8 100 0× Fig 12 Monel K-500, held 1 h at 1205 °C (2200 °F), transferred to a furnace at 595 °C ( 1100 . 96.5Ni-0.15C-0.25Mn-0.30Fe-0.63Ti-4.38Al Monel 400 66.5Ni-31.5Cu-0.15C-1.0Mn-1.25Fe Monel R-405 66.5Ni-31.5Cu-0.15C-1.0Mn-1.25Fe-0.043S Monel K-500 66.5Ni-29.5Cu-0.13C-0.75Mn-1.0Fe-0.60Ti-2.73Al. compositions of nickel and nickel-copper alloys Alloy Composition Nickel 200 99.5Ni-0.08C-0.18Mn-0.20Fe Nickel 270 99.98Ni-0.01C Permanickel 300 98.5Ni-0.20C-0.25Mn-0.30Fe-0.35Mg-0.40Ti Duranickel. 1. 4-1 .5 9-1 0 Nickel 270 1. 5-1 .8 1 0-1 2 Duranickel 301 1.2 5-1 .5 8-1 0 37 mL H 3 PO 4 (conc), 56 mL glycerol, 7 mL H 2 O Monel 400 0. 9-1 6-7 Etching. The solutions and conditions for etching