Effects of refinement of primary Si and residual stress on the mechanical properties of Aluminum B.390 alloy have been examined. Calcium was found to have an effect on the size of primary silicon particles. Primary silicon particle was refined as Ca content decreased. Refinement of primary Si particles led to an improvement in mechanical properties of the alloy; increase of elongation was prominent, above all. By the increase of compressive residual stress in the matrix alloy, tensile strength increased but elongation decreased.

Iodine-Induced Stress Corrosion Cracking (ISCC) properties of Zircaloy-4 and HANA4 developed in KAERI for the high burn-up nuclear fuel cladding were evaluated. To confirm the effect of final heat treatment on ISCC resistance of Zr-alloy, stress relieved and recrystallized specimens were prepared and tested. With the pre-cracked specimen at internal surface, ISCC crack propagation rates and threshold stress intensity factor ($K_{ISCC}$) based on the fracture mechanics were measured by internal pressurization test at $350^{\circ}C$ in iodine environment. $K_{ISCC}$ of Zircaloy-4 and HANA4 cladding were $3.3MPa{\cdot}m^{1/2}$ and $4.4MPa{\cdot}m^{1/2}$, respectively. Pitting corrosion at the crack surface was observed and it seemed that TG crack propagation was derived from the pitting.

Modern automobiles are built with a steadily increasing variety of materials and semifinished products. The traditional composition of steel sheet and cast iron is being replaced with other materials such as aluminum and magnesium. But low formability of these materials has prevented the application of the automotive components. The formability can be enhanced by conducting the warm hydroforming using induction heating device which can raise the temperature of the specimen very quickly. The specimen applied to the test is A6061, A7075 extruded tubes which belong to the age-hardenable aluminum alloys. But in the case of A6061 age hardening occurs at room temperature or at elevated temperatures before and after the forming process. In this study the effects of the heating condition such as heating time, preset temperature, holding time during die closing and forming time on the hydroformability are analyzed to evaluate the phenomena such as dynamic strain hardening and ageing hardening at high temperatures after the hydroforming process.

The steady state cyclic mechanism, and the behaviour of Nicoseal(Fe-29Ni-17Co) have been examined under the condition of square wave stress cyclic tension creep test at the temperature, stress and frequency range of $430{\sim}470^{\circ}C$($0.41{\sim}0.43T_m$), 353~383 MPa, and 3 cpm, respectively. Also, the relationship between cyclic creep and static creep have been examined. The stress exponents(n) for the static creep deformation of this alloy were 11.6, 10.0, 8.4 and 7.9 at the temperature of 430, 445, 460 and $470^{\circ}C$, respectively. The apparent activation energies (Q) for the static creep deformation were 54.2, 51.8, 49.7 and 46.8 kcal/mole for the stress of 353, 363, 373 and 383 MPa, From the above results, it could be considered that the cyclic creep accelaration phenomena was obtained and that the cyclic deformation for Nicoseal seemed to be controlled by dislocation climb over the range of experimental conditions. Nicoseal alloy under the cyclic creep conditions was obtained as P=(T+460)(logt+17). The failure plane observed by SEM showed up transgranular fracture at all range.

The effects of duplex-treatment of plasma carburization and CrN coating onto Ti-6Al-4V alloy on its creep properties were investigated by means of a constant stress creep tester. Applying duplex-treatment, specimens having an inner carburized layer of about $150{\mu}m$ in depth and outer CrN layer of about $7.5{\mu}m$ in thickness were prepared. The hardness of duplex-treatment surface was about 1,960 VHN. It also appeared that the duplex-treatment improved the roughness of the surface significantly; $Ra=0.045{\mu}m$ for treated alloy while $Ra=0.321{\mu}m$ for untreated alloy. The steady-state creep behaviors were investigated in a temperature range of $510{\sim}550^{\circ}C$ ($0.42{\sim}0.44T_m$) under an applied stress range of 200~275 MPa. The stress exponent, n, was derived assuming the power law creep behavior. The surface treatment showed a decrease in a value from 9.32 (untreated) to 8.79 (treated). Also the activation energy obtained from an Arrhenius plot increased from 238 to 257 kJ/mol.