Prediction of forming limits and microstructural evolution during warm stretch forming of DP590 steel

2021 ◽  
Vol 21 (3) ◽  
Author(s):  
Sandeep Pandre ◽  
Ayush Morchhale ◽  
Nitin Kotkunde ◽  
Swadesh Kumar Singh ◽  
Sujith Ravindran
Keyword(s):  
Microstructural Evolution ◽  
Stretch Forming ◽  
Forming Limits

On the Theories of Sheet Metal Necking and Forming Limits

1978 ◽  
Vol 100 (3) ◽  
pp. 303-309 ◽  
Author(s):  
A. S. Korhonen
Keyword(s):  
Sheet Metal ◽  
Present State ◽  
Sheet Metal Forming ◽  
Metal Forming ◽  
Strain Path ◽  
Plastic Instability ◽  
Stretch Forming ◽  
Theoretical Limit ◽  
Forming Limits ◽  
Localized Necking

The history and the present state of the theory of sheet metal forming limits are reviewed. The theory of necking and plastic instability (Swift-Hill and Marciniak-Kuczyn´ski models) is discussed and theoretical limit strains are calculated. The influence of the strain path on the theoretical limit strains is discussed with computational examples. At the present no theory can fully explain the localized necking in stretch forming.

Microstructural Evolution in Reduced TiO2

1981 ◽  
Vol 39 ◽  
pp. 74-75
Author(s):  
W. T. Donlon ◽  
S. Shinozaki ◽  
E. M. Logothetis ◽  
W. Kaizer
Keyword(s):  
Microstructural Evolution ◽  
Point Defects ◽  
Extended Defects ◽  
Small Deviations ◽  
Controlled Atmospheres ◽  
Limited Solubility ◽  
Thin Foils ◽  
Heat Treated ◽  
Porous Polycrystalline ◽  
Crystallographic Shear

Since point defects have a limited solubility in the rutile (TiO2) lattice, small deviations from stoichiometry are known to produce crystallographic shear (CS) planes which accomodate local variations in composition. The material used in this study was porous polycrystalline TiO2 (60% dense), in the form of 3mm. diameter disks, 1mm thick. Samples were mechanically polished, ion-milled by conventional techniques, and initially examined with the use of a Siemens EM102. The electron transparent thin foils were then heat-treated under controlled atmospheres of CO/CO2 and H2 and reexamined in the same manner.The “as-received” material contained mostly TiO2 grains (∼5μm diameter) which had no extended defects. Several grains however, aid exhibit a structure similar to micro-twinned grains observed in reduced rutile. Lattice fringe images (Fig. 1) of these grains reveal that the adjoining layers are not simply twin related variants of a single TinO2n-1 compound. Rather these layers (100 - 250 Å wide) are alternately comprised of stoichiometric TiO2 (rutile) and reduced TiO2 in the form of Ti8O15, with the Ti8O15 layers on either side of the TiO2 being twin related.

MICROSTRUCTURAL EVOLUTION OF DIRECTIONALLY SOLIDIFIED Ni--BASED SUPERALLOY DZ125 UNDER PLANAR GROWTH

2010 ◽  
Vol 46 (9) ◽  
pp. 1075-1080 ◽  
Author(s):  
Zhixian MIN ◽  
Jun SHEN ◽  
Lingshui WANG ◽  
Zhourong FENG ◽  
Lin LIU ◽  
...  
Keyword(s):  
Microstructural Evolution ◽  
Directionally Solidified ◽  
Planar Growth
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