著者

岡安 光博 西 直美 金沢 憲一

出版者

公益社団法人 日本鋳造工学会

雑誌

鋳造工学 (ISSN:13420429)

巻号頁・発行日

vol.70, no.4, pp.266-272, 1998-04-25 (Released:2011-02-01)

参考文献数

8

被引用文献数

4

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Effects of silicon content are investigated on tensile properties and crack propagation behavior of Al-Si-Cu alloy die castings. The specimens are made by the low velocity shot die casting method. Silicon content of alloy is varied from 8.6 mass % to 15.4 mass %. The tensile strength and the elongation of hypo-eutectic Al-Si alloys are higher than those of hyper-eutectic Al-Si alloys. In the case of hypo-eutectic Al-Si-Cu alloys, a crack propagates through the eutectic phase in inter-dendrite region or α-Al dendrite. In the case of hyper-eutectic silicon alloy, the primary silicon acts as the origin of fracture because primary silicon crystallizes with facet planes. The crack mainly propagates through primary silicon grains or along eutectic silicon. Primary silicon particles tend to segregate in case of low velocity injection casting. This macro-segregation of primary silicon particles deteriorates the mechanical properties. Especially tensile strength decreases with increase of segregation.

著者

馬場 康平 岡安 光博

出版者

一般社団法人 日本機械学会

雑誌

日本機械学会論文集 (ISSN:21879761)

巻号頁・発行日

vol.84, no.863, pp.17-00570, 2018 (Released:2018-07-25)

参考文献数

11

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Domain switching characteristics of a commercial lead zirconate titanate piezoelectric (PZT) ceramic at high temperature of 100℃ were investigated using an electron backscatter diffraction (EBSD) system. The PZT ceramic consisted of a tetragonal structure with grain size of about 5μm. To analyze the domain switching characteristics, the EBSD analysis was carried out in the same region of the PZT ceramic before and after the heating process. From this analysis, it appeared that each grain is formed by three different domains with different ratio. The area ratio of the domain was altered after the heating process because of the 90° domain switching. To understand clearly the 90° domain switching characteristics, the domain modes were categorized with the angle between the poling direction and c-axis of the tetragonal structure. Although the domain mode was categorized, no clear switching pattern was clarified, i.e., domain switching occurred randomly. Such domain switching mode was attributed to the complicated thermal stress in the PZT ceramic. In order to clarify the domain switching pattern under the heating process, the switching characteristics were investigated in details, in which the grain, having different stress distribution, was selected. The grain selected was constrained in the wide area by the other grains and some region was non-constrained due to the vacancy. From this analysis, severity of domain switching depended on the stress level, e.g., the higher compressive stress, caused by the thermal expansion of the other grains, made the strong domain switching.