In order to investigate the effect of plastic deformation and annealing process parameters on strength and electrical conductivity of Cu-Fe alloys, Cu-10wt%Fe, Cu-15wt%Fe alloys were drawn up to ${\eta}=4$ and annealed in the temperature range of $300^{\circ}C$ to $700^{\circ}C$, followed by measurements of tensile strength and electric conductivity. As draw strain increases, tensile strength increases while electrical conductivity decreases. These observations result from reduction of dislocation density and decrease in Fe fiber spacing. Raising annealing temperature brought about decrease of tensile strength and increase of electrical conductivity up to $500^{\circ}C$, being followed by decreasing above $500^{\circ}C$. Such results are thought to be caused by decrease of dislocation density below $500^{\circ}C$ and rapid solubility increase of Fe in Cu above $500^{\circ}C$. For the purpose of obtaining both high strength and high conductivity, annealing process should be incorporated just prior to reaching to final draw strain. For Cu-10wt%Fe alloy, the tensile strength 706.9 MPa and the electrical conductivity 54.34%IACS were obtained through the processes of drawing up to ${\eta}=3$, annealing at $500^{\circ}C$ for 1 hour and additional drawing up to total strain of ${\eta}=4$.

The effects of severe plastic deformation and heat treatment on the mechanical properties of Al 5052 and 6005 alloys were investigated using the metallurgical technique and nano-indentation technique in nano-surface region. Equal channel angular pressing (ECAP) was used to apply severe plastic deformation to the aluminum alloys in order to obtain fine grain sized materials. The elastic modulus was measured and interpreted in relation to the metallurgical observation. The elastic modulus increased after ECAP process due to evolution of the fine grains. However, the elastic modulus decreased after heat treatment due to generation of coarsened precipitates on the grain boundaries.

The aim of this study investigates the feasibility of scanning acoustic microscope (SAM) with high frequency transducer for material degradation. The test specimen was prepared by artificial heat treatment of Co-base superalloy. The high frequency 200 MHz acoustic lens was used to generate the leaky surface acoustic wave (LSAW) on the test specimens. The matrix precipitates coarsened with thermal aging time, and then grow up to several tens of micrometers. The velocity of LSAW decreased with increasing aging time. Also, it has a good correlation between LSAW and hardness. Consequently, V(z) curve methods of SAM using high frequency transducer is useful tool to evaluate the heat treatment effects on microstructure.

Friction stir welding is one of the interesting welding methods for titanium and its alloy which proceeds with plastic flow due to thermo-mechanical stirring and friction heat. Solid-state welding can solve severe problems such as high-temperature oxidation, interstitial oxygen diffusion and grain coarsening by liquid-state welding. Dynamic recrystallization and grain refinement can vary significantly with the plunging load and rotational speed of tool during friction stir welding, and suitable process conditions must be optimized to obtain microstructure and better mechanical characteristics. Suitable FSW conditions were 1000 kg of plunging load and 200 rpm of rotational speed and it showed YS 270 MPa, UTS 332.1 MPa, and El 17.3%, which were very similar to those of wrought titanium sheet.