The effects of alloy production method on microstructure and hence fatigue crack growth rate and fracture mechanism have been examined for a variety of fine-grained/high dispersoid Al-Li-Mg-Zr and Al-Li-Cu-Mg-Zr alloys. Microstructures have been assessed by scanning and transmission electron microcopy, together with electron back scattered diffraction pattern assessment. In these fine-grained/h...

The effect of microstructural refinement and intercritical annealing on the mechanical properties and work-hardening response of a low carbon St12 steel was studied. It was revealed that intercritical annealing of the ferritic-pearlitic sheet results in the formation of a coarse-grained DP microstructure with discrete martensite islands normally formed in place of pearlitic colonies, which resu...

The high strength Al-Zn-Mg alloy is widely used for structure components in critical aerospace applications. Small additions of scandium (Sc) often refine cast microstructure and mechanical properties by forming metastable Al3Sc dispersoids. The main role of the Al3Sc dispersoid is to prevent recrystallization during hot deformation and solution treatment. A new technique to apply for surface m...

This study reports the welded joint of a novel 590 MPa V-N microalloyed wheel steel on microstructure and mechanical properties after flash butt welding. The welding parameters were current 48°/582.0 A, upsetting 44°/516.6 workpiece clearance 1.5 mm. evolution in occurred as follows: seam (ferrite side plate + acicular ferrite +martensite)→coarse-grained zone (acicular granular bainite)→fine-gr...

in this paper, an ultra low carbon high strength low alloy grade steel was subjected to a two-step forging processand this was followed by different post cooling methods. the highest strength was obtained at a faster coolingrate due to the highly dislocated acicular ferrite structure with the fine precipitation of microalloying carbides andcarbonitrides. at a slow cooling rate, the strength fel...

B. Ahn*, S. R. Nutt 1. Department of Chemical Engineering and Materials Science, University of Southern California, Los Angeles, CA, 90089-0241, USA *[email protected] Abstract: Al–Mg alloy powder was mechanically milled in liquid N2 (cryomilling) to produce thermally stable powder with nanocrystalline (NC) microstructure for the manufacture of highstrength alloys. A multi-scale microstructure w...

Commercialised mechanically alloyed yttria dispersion strengthened alloys exhibit unusual recrystallisation behaviour. In spite of their large stored energy content, they tend to recrystallise at temperatures close to melting. The recrystallised microstructure is often very coarse and highly anisotropic, characterised by columnar grains. Such a microstructure is often referred to as being “dire...

Fracture toughness (K1C) of medium carbon steel (0.5% C) has been determined by round notched tensile specimen. Two notch diameters (5.6mm and 4.2mm) and three notch angles (α) namely 45, 60 and 75 have been used to observe the effect of notch diameters and notch angle on fracture toughness of the steel. By heat treatment the microstructure of the steel is also varied and its effect on the frac...