以擠壓鑄造法探討內造Ni-Al系介金屬複合材料

Abstract

摘 要 本研究係以擠壓鑄造法製作NiO/Al金屬基複合材料，然後再進行不同溫度的熱處理，以期能內造生成含有Al2O3強化相的Ni-Al介金屬基複合材料。根據示差熱分析的結果顯示，以純Al為基材，不同NiO的體積分率，其第一反應的活化能相差頗大，分別是166.80及237.95 kJ/mole，最後形成的複合材料亦不同，NiO-40(NiO 40 vol%)是NiO/Ni/Ni2Al3/Al2O3複合材料，NiO-20(NiO 20 vol%)是NiO/Ni/NiAl3/Ni2Al3/Al2O3複合材料。而以不同基材A356鋁合金，相同NiO體積分率(NiO 40 vol%)，發現相同的體積分率，所得到的複合材料是一樣的NiO/Ni/Ni2Al3/Al2O3，只是內造生成的Al2O3型態不同。 此外在1200 ℃熱處理後，NiO/Ni/Ni2Al3/Al2O3之介金屬基複合材料的熱膨脹係數為10.8 mm℃-1，硬度可達602 Hmv，密度則為4.89 g/cm3。

Abstract In this study, NiO/Al metal matrix composite was fabricated by squeeze casting. In situ synthesis of Al2O3 reinforcement and nickel aluminide intermetallic compound was successfully developed by phase transformation various service conditions. According to the differential thermal analysis (DTA), a marked variation in activation energy was observed at the first exthothermic peak, which was 166.80 and 237.95 kJ/mole, respectively, for aluminum matrix composition contained 40% and 20% NiO volume fractions. Both the NiO/Ni/Ni2Al3/Al2O3 and NiO/Ni/NiAl3/Ni2Al3/Al2O3 were formed by 40% and 20% volume fraction, respectively. However, for the same volume fraction (40% NiO) with A356 aluminum alloy as the matrix, it was found that the similar intermetallic compound was obtained but a different type of Al2O3 was produced by in situ synthesis. Moreover, some good physical properties were obtained in NiO/Ni/Ni2Al3/Al2O3 intermetallic compound, by the operating conditions aging temperature 1200°C for 1 hr. The coefficient of thermal expansion was 10.8 mm/°C, and hardness reached 602 Hmv as the density at 4.89 g/cm3.