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The present study investigated grain growth, recrystallization, and fatigue crack growth behavior of Al-Cu-Si alloy subjected to cryorolling and annealing treatment for 1 h. Temperature from 373 to 523 K was considered for this study. Cryorolling is used to produce ultra-fine-grained (UFG) structures, while annealing is used to study the recrystallization and grain growth. The fatigue crack growth (FCG) rate was measured in the low-stress intensity factor range (ΔK) (Stage II) and high-stress intensity factor ranges using the Paris equation and measuring the striation width. The results discovered that cryorolling led to a significant decrease in the fatigue crack growth resistance in the low-stress intensity factor range compared to coarse grain counterparts due to a decrease in the crack closure level in the cryorolled alloy. The results also showed that the fatigue crack growth resistance of the cryorolled alloy improved in the high-stress intensity factor range due to the formation of ultra-fine-grained microstructure, resulting in fine striations observed from the fractographic studies. The post-annealed samples at 373 K exhibited higher fatigue crack growth resistance in low and high-stress intensity factor ranges. High fatigue crack growth resistance in the annealed sample in low and high-stress intensity factor range is attributed to the fine semicoherent spherical phase θ . [ABSTRACT FROM AUTHOR]

Heat transfer with the jet impingement technique improves the heat transfer rate. Jet impingement is the only exceptional potential for heat transfer for wide industrial applications. This research aims to present a summary and finding of heat transfer improvement using various active and passive jet impingement techniques. In this article, we discuss about experimental and numerical results in the literature part and the research trends for determining the scope of future work. This work explores details about the active and passive jets, V-shaped jet plate, and absorber plate at different patterns and angles of 40–90°, along with nano-fluid that enhances the rate of heat transfer. The current study emphasizes single as well as double jets, and their outcomes are discussed in literature part. Heat transfer in the form of Nusslet number Nu and pumping power in the form of friction factor f assumed as 1000 W/m2 for Reynolds Number Re 2500–18,000 for solar air heater jet impingement (SAHJI) and smooth solar air heater (SSAH). The result shows enhancement of heat transfer 1.65 times and maximum hydraulic performance for SAHJI is 1.18. In similar condition, hydraulic performance is better for SAHJI as compared to SSAH. [ABSTRACT FROM AUTHOR]