Dynamic recrystallization phenomena during laser-assisted friction stir processing of a precipitation hardened nickel base superalloy

Mousavizade, S.M.; Pouranvari, M.; Ghaini, F. Malek; Fujii, Hidetoshi; Yangshan, Sun

doi:10.1016/j.jallcom.2016.06.209

Cited by 21 publications

(4 citation statements)

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“…Therefore, it can be inferred that the size and volume fraction of the γ′ in the SZ both were much lower than that of the BM, and similar results have been reported in Refs. [20,53,54]. Therefore, the contribution of precipitation strengthening of FSP samples was significantly lower than that of the BM.…”

Section: Effects Of Rotation Rate On Mechanical Propertiesmentioning

confidence: 89%

“…The grain structure in the SZ is controlled by DRX which is caused by high heat input and severe plastic deformation during FSP/FSW [20,37]. The DRX can significantly refine the grain size and reduce the deformation resistance, which is beneficial to improve the mechanical properties of the metals [40].…”

Section: Mechanism Of Grain Refinementmentioning

confidence: 99%

“…The γ′ precipitates in the BM are completely dissolved during the heating cycle of FSP because the temperature in the SZ exceeds the dissolution temperature of γ′ precipitates [53,54]. Then, only a fraction of fine γ′ reprecipitated during the rapid cooling, which is called reprecipitated γ′ [20,53]. Xu et al [53] reported that the diameter and volume fraction of reprecipitated γ′ in the friction welded joint of HT700 alloy were only 6.7 ± 0.9 nm and 8.9%, respectively, both of which were much smaller than those of the BM (35 ± 8 nm and 20%).…”

Section: Effects Of Rotation Rate On Mechanical Propertiesmentioning

confidence: 99%

“…Superalloys usually have a higher strength and harder plastic flow than other high-melting-point materials at elevated temperatures making it more challenging to apply FSP/FSW to them, so that only a few studies have been reported in this field [18,19]. To solve this problem, heatassisted FSW/FSP has been proposed to improve the rheological properties of the material [20,21]. However, the complex operation and introduced new parameters set strict limits on its application.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Rotation Rate on Microstructure and Mechanical Properties of Friction Stir Processed Ni–Fe-Based Superalloy

Wang

Huang

Xue

et al. 2021

Acta Metall. Sin. (Engl. Lett.)

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In this work, friction stir processing (FSP) was applied to the high-strength and high-melting-point Ni-Fe-based superalloy (HT700) for the first time with negligible wear of the stir tool. Different rotation rates were chosen to investigate the effect of heat input on microstructure and tensile properties at different temperatures of friction stir processed Ni-Fe-based superalloy. The results showed that with increasing rotation rate, the percentage of high-angle grain boundaries and twin boundaries gradually decreased whereas the grain size initially increased and then remained almost constant; the difference in tensile properties of FSP samples with rotation rates of 500-700 rpm was small attributing to their similar grain size, but the maximum strength was achieved in the FSP sample with a rotation rate of 400 rpm and traverse speed of 50 mm/min due to its finest grain size. More importantly, we found that the yield strength of all FSP samples tensioned at 700 °C was enhanced clearly resulting from the reprecipitation of γ′ phase. In addition, the grain refinement mechanism of HT700 alloy during FSP was proved to be continuous dynamic recrystallization and the specific refinement process was given.

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Section: Effects Of Rotation Rate On Mechanical Propertiesmentioning

confidence: 89%