Effect of deep cryogenic treatment on microstructures and performances of aluminum alloys: a review

Aluminum alloys are widely used in the fields like aerospace, automotive and manufacturing industries due to their excellent comprehensive performances and low mass and density. With the rapid development of the industries above mentioned, the requirements of aluminum alloys properties are increasingly raised. Therefore, it is especially significant to choose reasonable treatment methods to upgrade the related performances of aluminum alloys. As a green, low-cost and no pollution new heat treatment process, deep cryogenic treatment (DCT) can significantly improve the microstructures and performances of the metals with little variation in their sizes and shapes. The present paper summarizes the characteristics and mechanisms of the DCT influence on the structure-performance evolutions of aluminum alloys. When the DCT parameters are selected appropriately, ultra-low temperature can lead to refinement and preferred orientation of grains, increase of dislocation density and optimization of secondary phase distribution for aluminum alloys. Besides, mechanical properties, residual stress, corrosion resistance, wear resistance and electrical conductivity of aluminum alloys can be considerably improved due to the various microstructure evolutions induced by DCT. The present paper not only concludes major findings of the previous researches but also suggests future recommendations for aluminum alloys processed by DCT.