The structure and properties of HSLA steel obtained by Osprey forming process were investigated. The porosities were generated at the bottom of specimen due to the quenching effect of cold substrate during forming. The steel had a bainitic structure. The grain size were different among positions due to the cooling rates. The elements such as Mn, S, Si, Cr, Mo and etc. were contained in inclusions. They were formed at grain boundries. The size of them was $1{\sim}2{\mu}m$ and has nothing to do with the chemical composition. MnS and NbC were precipitated during rolling and aging.

Water and oil were completely synthesised with ultrasonic vibration energy irradiation. Pure Pb were added into Al melt during irradiated the ultrasonic vibration energy in 750. And the ultrasonic vibration energy was applied to Al-Pb melt to enhance the miscibility. Microstructural analysis, thermal analysis and X-ray diffraction analysis were carried out to evaluate the effect of the ultrasonic vibration energy on the castability and microstructural reliability. (1) Using the ultrasonic vibration energy irradiation, the complete mixing of water and oil was obtained. (2) The microstructure was refined by the application of ultrasonic vibration energy in Al-Pb alloys. (3) Relatively large Pb particles, $5{\mu}m$ were most distributed alone the grain boundaries with fine Pb particles evenly distributed in the matrix. (4) The solubility of Ph in Al-Pb alloys was increases up to 5% with the application of ultrasonic vibration energy.

Cast AZ91 and extruded AM50 alloys were isothermally heated as solid/liquid coexistent temperatures, and semi-solid formed into sheets. Mold filling ability of semi-solid slurry with different liquid fractions was investigated in relation to process variables such as injection speed and mold temperature. Relatively uniform distribution of solid particle size and liquid fraction were observed throughout the semi-solid formed sheet. AZ91 alloy sheets were also manufactured by conventional die casting and compared with the semi-solid formed. It was found that the surface was more smooth and the dimensional accuracy was higher in case of the semi-solid formed.

Ni-Nb-Ti-Zr amorphous alloys were manufactured using melt-spinning methods. Amorphous formability, the supercooled liquid region before crystallization and mechanical properties were examined. The value of the reduced glass transition temperature and the supercooled liquid region of $Ni_{62}Nb_{10}Ti_{13}Zr_{15}$ alloy were relatively high and were 0.612 and 76 K respectively. However, amorphous bulk alloy rod was not formed using the Cu-mold die casting. The mechanical properties were in the range of $800{\sim}900DPN$ of hardness and $2.5{\sim}2.8$ GPa of tensile strength in the whole composition range.

Effects of Ca content on the refinement of primary Si of Aluminum B390 alloy have been examined. Ca was found to have an effect on the refinement of primary Si particle. Primary Si particle size has been refined as Ca content of the melts decreased and cooling rate increased. A control of Ca content by the addition of $CuCl_2$ to the melt was the most efficient in the refinement of primary Si particles. The minimum size of primary Si particles in this study was $15.0\;{\mu}m$ when a residual content of Ca element in the alloy was 5ppm, Primary Si particle size was refined as primary Si crystallization temperature increased, which was attributed to the decrease of Ca content in the melts.

A novel jewelry master pattern manufacturing process which reduce manufacturing steps by employing a Duraform rapid prototyping mold and a low melting alloy has been suggested. The novel process follows the steps of 'jewelry 3D CAD design ${\rightarrow}$ Durafrom RP mold ${\rightarrow}$ low melting alloy master pattern' while the previous process follows more complicated steps of 'jewelry idea sketch ${\rightarrow}$ detailed drawing ${\rightarrow}$ wax carving ${\rightarrow}$ flask ${\rightarrow}$ silver master pattern.' An upper and a lower part of molds have been manufactured of Duraform powder, of which melting point is $190^{\circ}C$. A maser pattern was manufactured by pouring a low melting alloy of Pb-Sn-Bi-Cd, so called Woods Metal, of which melting point is $70^{\circ}C$, into the mold. The master pattern is a shape of a disk of 20mm diameter that contains various design factors. The variations of dimensions, surface roughness, surface pore ratio were measured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of were maeasured by an optical microscope, a surface roughness profilometer, and a Rockwell hardness tester. The pattern made of low melting alloy has sufficient surface hardness, and surface pore ratio to be used as the jewelry master pattern.