Precipitation and its Hardening Effect in Ni-Rich NiTi

Precipitation Hardening of Metal Alloys

Precipitation hardening, or age hardening, provides one of the most widely used mechanisms for the strengthening of metal alloys. The fundamental understanding and basis for this technique was established in early work at the U. S. Bureau of Standards on an alloy known as Duralumin [1,2]. Duralumin is an aluminum alloy containing copper and magnesium with small amounts of iron and silicon. In a...

Precipitation hardening in dilute Al–Zr alloys

The aim of this study was to investigate the effect of solute content (hipoperitectic Al–0.22 wt.%Zr and hiperperitectic Al–0.32 wt.%Zr) on the precipitation hardening and microstructural evolution of dilute Al–Zr alloys isothermally aged. The materials were conventionally cast in a muffle furnace, solidified in a water-cooled Cu mold and subsequently heat-treated at the temperature of 650 K (3...

Precipitation Hardening of Al–Si–Mg Alloys

Effect of copper on precipitation and baking hardening behavior of Al−Mg−Si alloys

The effects of copper on the ageing precipitation behavior of as-quenched and pre-aged AA6016 aluminum alloy were studied by differential scanning calorimetry (DSC), Vickers hardness measurement and transmission electronic microscopy (TEM). The results indicate that the addition of copper facilitates the growth of clusters (GP I) to the critical size during pre-ageing. Therefore, the addition o...

Recovery of strain-hardening rate in Ni-Si alloys

In this study, the recovery of strain-hardening rate (RSHR) was discovered for the first time in polycrystalline materials (Ni-Si alloys) that have only dislocation activities during tensile test. Detailed microstructure characterizations show that the activation of dislocations in the secondary slip systems during tensile deformation is the major reason for this RSHR. By taking into account ot...