The objective of this work is to study the effect of room temperature (RT) and liquid nitrogen temperature (LNT) rolling on mechanical properties of the pure copper. For the same percentage deformation, LNT samples show a significant increase in tensile strength and hardness value compared to RT samples. Microstructural investigation shows a large misorientation change between RT and LNT samples when we use grain orientation spread (GOS) as a measure of microstructural change. The mechanical property and microstructural changes are correlated with calorimetry experiments. We also present some preliminary results from our work on wire drawing at RT and LNT. 相似文献
In this paper, NiAl-33Cr-4.5Ta (at. pct) near-eutectic alloy consisting of NiAl, α-Cr and Laves is successfully designed by JMatPro software and verified by experiments. TEM result reveals that it exists an orientation relationship between each two phases. Directionally solidified (DS) alloy has a well-aligned microstructure and possesses a fracture toughness (9.8 MPa·m1/2). Moreover, the DS alloy has a tensile ductility (1.4 pct) at room temperature. Fracture behavior is analyzed by the crack propagation and fracture surface.
Different multilayer Mg AZ31 and SS304L steel sheet combinations were prepared with different volume fractions of Mg. Isolated stress–strain curves of the Mg layers showed significant improvements in the strength and elongation of multilayer samples. Results indicated that in the most extreme situation with the lowest Mg volume fraction (Vf = 0.39), the ultimate strength was increased by 25 pct to 370 MPa and the elongation was improved by 70 pct to 0.34. Investigation of the fracture surface showed that failure occurs by the coalescence of cracks close to the interface region. The improved strength of the multilayer samples was due to the combined effect of surface crack prevention by the steel layer and the higher work-hardening rate caused by the possible increased activity of non-basal systems. It is suggested that the stronger work-hardening behavior and the enhanced activity of non-basal systems in the multilayer samples were due to the formation of new stress components in the transverse direction. The larger the volume fraction of steel in the multilayer, the longer the distance remaining unstrained before the UTS.