Details

Autor(en) / Beteiligte

• Wang, Ruiqian
• Liu, Wei
• Yao, Mengjia

Titel

Cooperative effect of grain size and cryogenic temperature on deformation behavior and mechanism of commercial pure Al sheets

Ist Teil von

• Materials science & engineering. A, Structural materials : properties, microstructure and processing, 2024-05, Vol.899, p.146411, Article 146411

Ort / Verlag

Elsevier B.V

Erscheinungsjahr

2024

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• In this paper, the effect of grain sizes on mechanical properties and microstructure evolution of pure Al sheet at cryogenic temperatures were studied by uniaxial tensile tests and microstructure observations. The results show a great exciting strain hardening ability for the sheet with ultra-fine grain (UFG) at cryogenic temperature, and the cooperative increasing in strength and ductility of pure Al at cryogenic temperatures become more and more prominent with the decrease of grain size. With the decrease of grain size, the increase of yield strength by decreasing temperature becomes more dramatic. The mechanism of increase in yield strength at cryogenic temperatures is attributed to the contribution of three temperature-dependent factors: grain boundary strengthening, lattice friction resistance and dislocation strengthening, in which grain boundary strengthening plays a dominant role. The grain size dependence of the strain hardening ability increased with decreasing temperature is mainly related to the inhibition of cross-slip in the grain interiors and the dislocation annihilation at grain boundaries, so that dislocation can effectively multiply and accumulate, which is totally different from the strain softening and poor plasticity of UFG pure Al at room temperature (RT) caused by the enhanced dislocation annihilation. As a result, the trade-off relationship between the strength and plasticity caused by different grain sizes is significantly weakened at cryogenic temperatures, which provides a very potential method for the complex parts forming of UFG sheets and mechanical properties improvement. •The increase of yield strength with decreasing temperature is more significant with decreasing grain size.•The increase of yield strength at cryogenic temperatures is mainly attributed to grain boundary strengthening.•The enhancements in uniform elongation at cryogenic temperatures become more prominent with the decrease of grain size.•With the decrease of temperature, the UFG pure Al gradually transitions from strain softening to strain hardening.•The trade-off relationship between the strength and plasticity is significantly weakened at cryogenic temperatures.