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Two cast noncombustible Mg–9Al–1Zn–1Ca alloys (composition in mass%) with coarse and fine initial microstructures were hot forged by compression at temperatures of 523–603 K and a true strain rate of 1–10−2 s−1. The compressive stress–strain curves for the two alloys were similar and typical of metals undergoing dynamic recrystallization (DRX). The alloy with the coarse initial microstructure suffered from edge crack formation during hot forging, while the alloy with the fine initial microstructure exhibited smooth peripheral surfaces after hot forging at temperatures of 573 K and above. The reduction of grain size by DRX was similar in the two hot-forged alloys, but the recrystallized volume fraction was lower in the alloy with the coarse initial microstructure. Insoluble second phases (seemingly Al2Ca) provide additional DRX sites, and thus it is expected that the finer initial cast microstructure will improve the microstructure in the resulting hot-forged Mg parts.

A 1/4-inch VGA wide-dynamic-range complementary metal oxide semiconductor (CMOS) image sensor with resistance to high temperatures has been developed using a lateral overflow capacitor in a pixel, a very low dark-current front-end-of-line (VLDC FEOL) , and either an inorganic cap layer on an on-chip-micro-lens (OCML) or a metal hermetically sealed package to suppress the degradation of the spectra response of the OCML and color filter. The dark current level was reduced to 25e-/sec/pixel at 60°C. Sensor chips with no cap and ones with the inorganic cap layer on the OCML were assembled into either a metal hermetically sealed package or a conventional package. The chips with the inorganic cap layer and the ones with the metal hermetically sealed package showed no significant degradation of the spectra response in any of the R/G/B pixels even after a thermal stress test at 150°C. Improved image sensing performances were observed up to 85°C, and the dynamic range was extended to 94dB.

In order to improve on the quality of Al–Si alloy billets, which are used as the feed stock for precision forging, a new vertical semi-continuous casting process has been adopted using a heat insulating and rapid cooling mold (HI-RCM) casting process. In our study, 4032 aluminum alloy billets with smooth surfaces have been obtained by controlling casting rates of HI-RCM process. Distributions of primary silicon, eutectic structure and secondary dendrite arm spacing (DAS) in the conventional DC casting billets were compared with the smooth surface billets fabricated by HI-RCM casting process under optimum conditions, and the latter one had finer and more homogeneous microstructures than those in the former billets.

A hypereutectic Al-Si-Cu-Mg alloy billet was fabricated by a semi-solid forming method that combined a simple mechanical stirring treatment with the vertical semi-continuous casting process. Higher rotational speeds and higher casting temperatures during stirring yielded a finer as-cast structure and more uniform distribution of primary silicon particles in the matrix. However, these stirring conditions also led to transverse cracks on the billet surface. A mechanical vibration treatment using smaller amplitudes and lower frequencies during casting improved the cracked surface considerably, resulting in a structure comparable to that of the billet stirred at the same time.

In order to obtain a superior thixotropic property even in a high strength 7075 aluminum alloy, a billet of an Al-5.5%Zn-2.5%Mg-1.5%Cu alloy with a nondendritic fine-grained structure has been tried to produce by combining a simple mechanical stirring with the vertical semi-continuous casting process. We succeeded to get a good quality billet on the basis of the trials that had been carried out under the various stirring conditions, especially focussing on the position of a stirring rotor, the shape of a rotor and the volume of a stirring chamber. When the temperature within a stirring chamber was nearly constant just below the liquidus temperature and dropped drastically near the liquid-solid interface during casting, a long sound billet with relatively smooth surface could be produced. And the billet had not only a uniformly fine-grained structure with the average grain size of ∼30 μ m, but also little macroscopic segregation of the solute elements along the radius at the various positions of the billet.

The effects of homogenizing treatment and iron content on the tensile properties of 6061 aluminum alloy billet were investigated mainly by tensile test and transmission electron microscopic observation. With the specimens produced by the vertical semi-continuous casting process, the iron content is 0.18, 0.7 and 1.4 mass%, the DAS is 9 and 25 μm, and the grain size is constant at about 80 μm. In the 0.18 mass% Fe alloy, elongation in as-cast is larger in DAS–9 μm than in DAS–25 μm. If they were air cooled after the homogenizing treatment, the difference in elongation between them is decreased with the increase of homogenizing time. On the other hand, if these samples were water quenched after the homogenizing treatment, even when DAS is different, no difference in elongation was found. The cause for this was presumed to be that the cooling condition after the homogenizing treatment accelerated the fracture of specimens by precipitating a coarse β' phase in the air cooling, and its elongation was reduced. It was revealed that the second phase formed between dendrite arms increased with the increase of iron content, the smaller the DAS is, the larger the elongation, and the difference of DAS did not disappear even in a long time homogenizing treatment.

A method to control grain size and DAS (secondary dendrite arm spacing) independently was established by the vertical semi-continuous casting process with a heat insulating mold, and the effects of grain size and DAS on the tensile properties of 6061 aluminum alloy billets were investigated. The grain size and DAS were controlled by changing casting rate and additional amount of a grain refiner. The Hall-Petch relation is obtained between grain size and 0.2% proof stress, but it's not obtained between DAS and 0.2% proof stress. DAS affects significantly the elongation, and the elongation increases as DAS decreases, but the effect of DAS on the elongation diminishes as a homogenization proceeds.

In the mathematical model developed, the mechanical energy for extrusion translated into the terms of heat produced during deformation as well as increasing in temperature, and changes in the deformation-resistance and frictional-resistance were calculated. The change of extrusion speed could be attained on the assumption that the maximum extrusion pressure was maintained until the preset extrusion speed was reached. The characteristics of die can be estimated at the stage of die design. By the improved die design using this model, the extrusions of larger and more complicated shapes can be produced.

The skin of a 6063 aluminum alloy billet folds inward during the direct hot extrusion. To examine the metal flow, a 6063 billet was sliced along the meridian plane and grids were etched on this plane. The metal flow was measured at the beginning, middle and end of the extrusion process from distortions of the grids. To examine the metal flow at the back end of the billet, 4 bands were carved near the end of the billet and these bands were filled with 4043 aluminum alloy. The metal flow at the back end were measured similarly from distortions of 4 bands. Ater 4 different-length billets were extruded, the unextruded remainders were cut in half in order to observe the metal flow. These remainders were then covered with anodic oxide film in a H2SO4 bath and colored electrolytically in a Ni-salt bath. These experiments show that the skin near the back end of the billet folds into the billet during the compression of the first stage of the extrusion. The folded length of the skin near the back end of the billet is directly correlated to the ratio determined by the billet diameter and the container diameter. By decreasing the clearance between the container and the billet, this folded length can be decreased.

A temperature resistant wide dynamic range (WDR) CMOS image sensor has been developed using the very low dark current front-end of line (VLDC FEOL) and the metal hermetic seal ceramic leadless chip carrier (CLCC) package suppressing the degradation of the spectra response of the on-chip micro lens and color filter (OCML/OCCF). A 1/4 inch VGA 5.6 μm pixel pitch WDR CMOS image sensor has been fabricated through 0.18 μm 2P3M process with the VLDC FEOL which contains the pinned photodiode with less electrical fields, the less plasma etching damages, the transfer gate with the suppressed current at Si-SiO2 interface and the furnace temperature process for the recrystallization. The sensor chips with the conventional OCML/OCCF assembled into the metal hermetic seal package by the low residual oxygen vacuum welding machine has finally received the thermal stress test (150 deg.C/500 hours). The dark current is 350 pA/cm2 at 85 deg.C (50 pA/cm2 at 60 deg.C). No degradation of the spectra response in any of R/G/B pixels is observed after the thermal stress test. It is found that the thermal decomposition of the OCML/OCCF (phenol resin) is not caused easily in nitrogen with the low residual oxygen concentration. The sample images captured by the WDR CMOS image sensor assembled camera keep good quality up to 85 deg.C.

CW laser operation in the 2.7–2.8 μm region has been observed in Er3+ doped fluorozircoaluminate glass fibres by diode laser pumping at 0.8 μm. An absorbed threshold power of 10 mW and an output laser power of 2.1 mW with a slope efficiency of 8% were obtained.