Hot Deformation Behavior and Microstructure Evolution of Cu–Ni–Co–Si Alloys

Abstract

The Cu-1.7Ni-1.4Co-0.65Si (wt%) alloy is hot compressed by a Gleeble-1500D machine under a temperature range of 760 to 970 °C and a strain rate range of 0.01 to 10 s−1. The flow stress increases with the extension of strain rate and decreases with the rising of deformation temperature. The dynamic recrystallization behavior happens during the hot compression deformation process. The hot deformation activation energy of the alloy can be calculated as 468.5 kJ/mol, and the high temperature deformation constitutive equation is confirmed. The hot processing map of the alloy is established on the basis of hot deformation behavior and hot working characteristics. With the optimal thermal deformation conditions of 940 to 970 °C and 0.01 to 10 s−1, the fine equiaxed grain and no holes are found in the matrix, which can provide significant guidance for hot deformation processing technology of Cu–Ni–Co–Si alloy.

Recent Progress on Patterning Strategies for Perovskite Light‐Emitting Diodes toward a Full‐Color Display Prototype

“…Reproduced with permission. [ 49 ] Copyright 2019, American Chemical Society. d) Schematic diagram of the “swelling–deswelling” of in situ formation of perovskite nanocrystals.…”

“…An alternative strategy to obtain highly emissive perovskite emitters through the inkjet printing methods is in situ formation of perovskite nanocrystals through the incorporation of additional additives, such as, polyvinylpyrrolidone (PVP), [ 49 ] into the precursor solutions. These introduced additives have functionality in both tuning the printable properties of the inks and controlling the final morphology as well as annihilating the defects in the perovskite patterns.…”

“…[ 52 ] Accordingly, a possible protocol to overcome the aforementioned unprintability issue is to increase the temperature of the nozzle as well as the precursor solutions to modulate the viscosity of the precursor inks. Through incorporating PVP into perovskite precursor solutions and adjusting the nozzle temperature, highly emissive perovskite nanocrystals with uniform size (≈30 nm) distribution and smooth morphology were obtained, [ 49 ] as shown in Figure 5c. Shi et al also reported in situ formed perovskite nanocrystals through a “swelling–deswelling” strategy in which perovskite precursors in DMSO or DMF were printed onto preheated polymer substrates, [ 53 ] such as, polymethyl methacrylate (PMMA), polystyrene (PS), and polyvinylidene fluoride (PVDF).…”

Constitutive Equation and Hot Processing Map of Mg-16Al Magnesium Alloy Bars

“…The Arrhenius-type constitutive equation has been widely used to describe the changing characteristics of flow stress and deformation temperature and strain rate [ 18 , 19 , 20 , 21 ]. However, only a few reports have considered the high temperature plastic deformation behavior of deformed Mg alloys with high Al content.…”

Constitutive Equations for Describing the Hot Compressed Behavior of TC4–DT Titanium Alloy

“…A similar result was obtained by developing constitutive models of 21–4 N heat resistant steel [ 9 ]. Moreover, the strain-compensated Arrhenius-type equation is most widely applied to describe the high-temperature flow behavior of metals and alloys [ 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. These results mean that the strain-compensated Arrhenius-type model has a relatively strong predictive ability.…”