Recrystallization, Grain Growth in Copper Foil at High Temperature Studied By Electron Back Scatter Diffraction

Author(s):  
Pragya Tiwari ◽  
Himanshu Srivastava ◽  
Sanjay Rai ◽  
S. K. Deb ◽  
Alka B. Garg ◽  
...  
Author(s):  
R. E. Franck ◽  
J. A. Hawk ◽  
G. J. Shiflet

Rapid solidification processing (RSP) is one method of producing high strength aluminum alloys for elevated temperature applications. Allied-Signal, Inc. has produced an Al-12.4 Fe-1.2 V-2.3 Si (composition in wt pct) alloy which possesses good microstructural stability up to 425°C. This alloy contains a high volume fraction (37 v/o) of fine nearly spherical, α-Al12(Fe, V)3Si dispersoids. The improved elevated temperature strength and stability of this alloy is due to the slower dispersoid coarsening rate of the silicide particles. Additionally, the high v/o of second phase particles should inhibit recrystallization and grain growth, and thus reduce any loss in strength due to long term, high temperature annealing.The focus of this research is to investigate microstructural changes induced by long term, high temperature static annealing heat-treatments. Annealing treatments for up to 1000 hours were carried out on this alloy at 500°C, 550°C and 600°C. Particle coarsening and/or recrystallization and grain growth would be accelerated in these temperature regimes.


Alloy Digest ◽  
1980 ◽  
Vol 29 (12) ◽  

Abstract SOMERS LTA Copper is a wrought copper foil that can be annealed at 350 F in 15 minutes to the full-soft condition; its use simplifies the manufacture of printed circuits (LTA = Low-Temperature Annealable). LTA Copper is especially useful for foil weights up to and including one ounce per square foot (0.0014-inch thick) for laminating to high-temperature dielectric substrates. This datasheet provides information on composition, physical properties, and elasticity as well as fatigue. It also includes information on forming, heat treating, and machining. Filing Code: Cu-407. Producer or source: Olin Corporation.


Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 171
Author(s):  
Fatim-Zahra Mouhib ◽  
Fengyang Sheng ◽  
Ramandeep Mandia ◽  
Risheng Pei ◽  
Sandra Korte-Kerzel ◽  
...  

Binary and ternary Mg-1%Er/Mg-1%Er-1%Zn alloys were rolled and subsequently subjected to various heat treatments to study texture selection during recrystallization and following grain growth. The results revealed favorable texture alterations in both alloys and the formation of a unique ±40° transvers direction (TD) recrystallization texture in the ternary alloy. While the binary alloy underwent a continuous alteration of its texture and grain size throughout recrystallization and grain growth, the ternary alloy showed a rapid rolling (RD) to transvers direction (TD) texture transition occurring during early stages of recrystallization. Targeted electron back scatter diffraction (EBSD) analysis of the recrystallized fraction unraveled a selective growth behavior of recrystallization nuclei with TD tilted orientations that is likely attributed to solute drag effect on the mobility of specific grain boundaries. Mg-1%Er-1%Zn additionally exhibited a stunning microstructural stability during grain growth annealing. This was attributed to a fine dispersion of dense nanosized particles in the matrix that impeded grain growth by Zener drag. The mechanical properties of both alloys were determined by uniaxial tensile tests combined with EBSD assisted slip trace analysis at 5% tensile strain to investigate non-basal slip behavior. Owing to synergic alloying effects on solid solution strengthening and slip activation, as well as precipitation hardening, the ternary Mg-1%Er-1%Zn alloy demonstrated a remarkable enhancement in the yield strength, strain hardening capability, and failure ductility, compared with the Mg-1%Er alloy.


1996 ◽  
Vol 23 (6) ◽  
pp. 739 ◽  
Author(s):  
PJ Stone ◽  
ME Nicolas

Short periods of very high temperature (> 35�C) are common during the grain filling period of wheat, and can significantly alter mature protein composition and consequently grain quality. This study was designed to determine the stage of grain growth at which fractional protein accumulation is most sensitive to a short heat stress, and to examine whether varietal differences in heat tolerance are expressed consistently throughout the grain filling period. Two varieties of wheat differing in heat tolerance (cvv. Egret and Oxley, tolerant and sensitive, respectively) were exposed to a short (5 day) period of very high temperature (40�C max, for 6 h each day) at 5-day intervals throughout grain filling, from 15 to 50 days after anthesis. Grain samples were taken throughout grain growth and analysed for protein content and composition (albumin/globulin, monomer, SDS-soluble polymer and SDS-insoluble polymer) using size-exclusion high-performance liquid chromatography. The timing of heat stress exerted a significant influence on the accumulation of total wheat protein and its fractions, and protein fractions differed in their responses to the timing of heat stress. Furthermore, wheat genotype influenced both the sensitivity of fractional protein accumulation to heat stress and the stage during grain filling at which maximum sensitivity to heat stress occurred.


Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 707 ◽  
Author(s):  
Jaromir Moravec ◽  
Iva Novakova ◽  
Jiri Sobotka ◽  
Heinz Neumann

The welding of fine-grained steels is a very specific technology because of the requirement for the heat input limit value. Applying temperature cycles results in an intense grain growth in a high-temperature heat-affected zone (HAZ). This has a significant effect on the changing of strength properties and impact values. The intensity of grain coarsening in the HAZ can be predicted based on the experimentally determined activation energy and material constant, both of which define grain growth kinetics. These quantities, together with real measured welding cycles, can be subsequently used during experiments to determine mechanical properties in a high-temperature HAZ. This paper shows a methodical procedure leading to the obtainment of the material quantities mentioned above that define the grain growth, both at fast and slow temperature cycles. These data were used to define the exposure temperature and the soaking time in a vacuum furnace to prepare test samples with grain sizes corresponding to the high-temperature HAZ of welded joints for the testing procedures. Simultaneously, by means of the thermo-mechanical simulator Gleeble 3500, testing samples were prepared which, due to a temperature gradient, created conditions comparable to those in the HAZ. The experiments were both carried out with the possibility of free sample dilatation and under a condition of zero dilation, which happens when the thermal expansion of a material is compensated by plastic deformation. It has been found that shape of the temperature cycle, maximal achieved cycle temperature, cooling rate, and, particularly, the time in which the sample is in the austenite region have significant effects on the resulting change of properties.


2011 ◽  
Vol 492 ◽  
pp. 250-255
Author(s):  
Bing Shen ◽  
Hua Wang ◽  
Shuai Li ◽  
Jiang Hong Gong

Grain growth in Ga2O3and MnO co-doped ZnO was investigated for sintering from 950° to 1250°C in air. Microstructural observation revealed that the samples sintered at lower temperatures consist of uniform equiaxed grains while the samples sintered at higher temperatures consist of plat-like grains, implying that the grain growth mechanism for the examined ZnO ceramics changes when the sintering temperature increases above about 1150°C. The traditional kinetic grain growth equation was employed to analyze the variation of grain size with sintering temperature and sintering holding time. It was shown that the grain growth exponent,n, increases from 2.17 for samples with uniform equiaxed grain structure to 4.30 for samples with plate like grain structure, while the apparent activation energy,Q, increases from 237 kJ/mol for low-temperature-sintered sample to 405 kJ/mol for high-temperature-sintered samples. The increases in bothnandQwere mainly attributed to the difference between the grain morphologies in low- and high-temperature ranges. The underestimation of the sizes of the plate-like grains was also considered to be another important origin for the higher values ofnandQfor the high-temperature-sintered samples.


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