Hot working of aluminum alloy 7075
Large deformation, constant true strain rate, isothermal compression tests have been conducted on the aluminum alloy 7075 at strain rates which ranged from 103 to 1 sec1 and temperatures which spanned the practical forging temperature range of 3250C 4250 C. In this strain rate and temperature regime the stress-strain curves show very little strain hardening or softening, and the relationship between the (visco) plastic strain rate iP, the absolute temperature T, and the flow stress a can be represented well by the classical one-dimensional equation:
Grain and Subgrain Structures Developed by Hot Working in As-Cast 434 Stainless Steel
58 INTRODUCTION 58 EXPERIMENTS 58 STRENGTH AND CONSTITUTIVE RESULTS 59 MICROSTRUCTURAL RESULTS 61 DISCUSSION 61 CONCLUSIONS 63 ACKNOWLEDGEMENTS 65 REFERENCES 66
Shape and surface texture of molten droplets deposited on cold surfaces
When a molten droplet impacts on a cold surface, the interaction between solidification and fluid dynamics can lead to different shapes and surface textures of deposited droplets. This article presents an experimental study on deposition of small droplets (39 μm diameter) of molten wax ink on solid surfaces. Our results show that both the final shape and the surface texture of deposited droplets are extremely sensitive to deposition conditions, which include initial temperature of droplets, type of substrate surface and distance between substrate and printhead. Different surface textures are observed and shown to depend on the thermal and flow histories of ink droplets during the process of impact. A test using crystalline wax reveals crystallization as one of the major factors in determining the final texture.