@article{article_341709, title={Effect of Diffusion Annealing Temperature on Crack-initiating Omnipresent Flaws, Void/crack Propagation and Dislocation Movements Along Ni Surface-layered Bi-2223 Crystal Structure}, journal={Sakarya University Journal of Science}, volume={22}, pages={1211–1220}, year={2018}, DOI={10.16984/saufenbilder.341709}, author={Turgay, Tahsin and Yıldırım, Gürcan}, keywords={Bi-2223 crystal structure,Ni impurity diffusion,annealing temperature,cracks/voids,dislocations}, abstract={<font size="3"> </font> <p style="margin:0cm 0cm 0pt;text-align:justify;line-height:150%;"> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;" xml:lang="en-us">This study aims to find out the crucial variations in the </span> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;" xml:lang="en-us">mechanical <span>
performance and characterization of Bi-2223 superconducting compounds with the
diffusion annealing temperatures </span>interval 650 °C-850 °C <span>by means of Vickers hardness measurements
exerted at the different applied </span>indentation <span>test loads ( </span>0.245 N-2.940 N) and derived theoretical findings. All
the experimental measurement results and theoretical evidences declare that the
mechanical characterization and performance are obtained to improve with the
increment in the diffusion annealing temperature up the value of 700 °C as a
consequence of decrement in the grain boundary coupling problems, local
structural distortions, grain misorientations, lattice strains, lattice
defects, disorders and </span> <a title="" href="http://en.wikipedia.org/wiki/Dislocation"> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;text-decoration:none;" xml:lang="en-us"> <u>dislocations </u> </span> </a> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;" xml:lang="en-us"> in the adjacent layers. Namely, the optimum annealing
temperature of 700 °C resulting in <span style="background:rgb(255,255,255);"> the optimum penetration
of Ni impurities </span>into both the superconducting grains and over the grain
boundaries develops the <span style="background:rgb(255,255,255);">crystallinity of Bi-2223
crystal structure. In other words, </span>the surface energy related to the
crack-initiating omnipresent flaws, void/crack propagation and dislocation
movement reduces due to the augmented critical stress value. In this respect,
the diffusion annealing temperature of 700 °C develops the <span style="background:rgb(255,255,255);">mechanical </span>durability, stiffness, <span style="background:rgb(255,255,255);">ideal </span>fracture and flexural strength. However,
after the certain diffusion annealing temperature value of 700 °C, the <span style="background:rgb(255,255,255);">crystallinity tends to degrade considerably and in
fact dwelling in the worst crystal structure for </span>850 °C annealing
temperature <span style="background:rgb(255,255,255);">. Accordingly, t </span>he initial
crack growths, sizes of crack-producing flaws, void/crack propagation and
dislocation movement in the </span> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;" xml:lang="en-us">copper-oxide consecutively stacked layers reac </span> <span lang="en-us" style="line-height:150%;font-family:’Times New Roman’, serif;font-size:12pt;" xml:lang="en-us">h much more rapidly to the critical speeds due to the
increased stress amplification so that the Bi-2223 compound with the augmented
brittle behavior breaks at even lower test load. <span style="background:rgb(255,255,255);"> </span>Moreover, it is observed that the presence of optimum nickel impurities
in the crystal structure strengthens the <span style="background:rgb(255,255,255);"> </span>standard <span style="background:rgb(255,255,255);"> </span>indentation size effect behavior. </span> </p> <font size="3"> </font>}, number={5}, publisher={Sakarya University}