The bulk materials were prepared by using standard metallographic methods, so that the samples could be glued on SEM specimen mounts. Bulk samples were carefully cut by using a diamond wire saw (Walter Ebner GmbH, Germany). They were then hand ground with silicon carbide particles of decreasing grit size down to 5 µm using a custom-made stainless steel cylindrical holder that was employed to produce samples. Subsequently, the samples were electropolished to reduce the damage produced by the harsh cutting and grinding procedures, and to obtain a flat surface needed for the later microcompression experiments. The electropolishing conditions used for each of the samples are summarized in the following table (Table 3.1). Table .: Electropolishing conditions of the different samples. Sample Parameter Solution 97% distilled and 3% NaOH W Voltage 20 V Time 40 sec Solution 95% CH3OH and 5% H2SO4 Ta Voltage 34 V Time 30 s Solution 60 wt% and distilled water Voltage 1.5 V β-CuZn Time 4 min Solution Struers electrolyte A2-I and A2-II (C2H6O, C6H14O2, HClO4, H2O) NiAl Voltage 33 V Time 90 s The W and Ta samples were mounted onto SEM using silver-based electrically and thermally conductive paste (Pyro-Duct 597-A, Aremco Products, New York, NY), which is suitable for elevated-temperature usage. The bonded arrangement was then cured at 70 °C and degassed in vacuum in a furnace (Gero Hochtemperaturöfen, Neuhausen, Germany) to avoid additional hydrocarbon contamination of the SEM used to carry out further compression tests at high temperatures. The and NiAl in situ β-CuZn samples were glued onto an aluminum holder using conventional silver paste (Acheson Henkel Silver DAG 1415, Germany), which is widely used for electron microscopy purposes.
The bulk materials were prepared by using standard metallographic methods, so that the samples could be glued on SEM specimen mounts. Bulk samples were carefully cut by using a diamond wire saw (Walter Ebner GmbH, Germany). They were then hand ground with silicon carbide particles of decreasing grit size down to 5 µm using a custom-made stainless steel cylindrical holder that was employed to produce samples. Subsequently, the samples were electropolished to reduce the damage produced by the harsh cutting and grinding procedures, and to obtain a flat surface needed for the later microcompression experiments. The electropolishing conditions used for each of the samples are summarized in the following table (Table 3.1). Table .: Electropolishing conditions of the different samples. Sample Parameter W Solution Voltage Time 97% distilled and 3% NaOH 20 V 40 sec Ta Solution Voltage Time 95% CH3OH and 5% H2SO4 34 V 30 s β-CuZn Solution Voltage Time 60 wt% and distilled water 1.5 V 4 min NiAl Solution Voltage Time Struers electrolyte A2-I and A2-II (C2H6O, C6H14O2, HClO4, H2O) 33 V 90 s The W and Ta samples were mounted onto SEM using silver-based electrically and thermally conductive paste (Pyro-Duct 597-A, Aremco Products, New York, NY), which is suitable for elevated-temperature usage. The bonded arrangement was then cured at 70 °C and degassed in vacuum in a furnace (Gero Hochtemperaturöfen, Neuhausen, Germany) to avoid additional hydrocarbon contamination of the SEM used to carry out further in situ compression tests at high temperatures. The β-CuZn and NiAl samples were glued onto an aluminum holder using conventional silver paste (Acheson Henkel Silver DAG 1415, Germany), which is widely used for electron microscopy purposes.
original_Thesis_OscarTorrents.docx