Modulus and hardness evaluation of polycrystalline superconductors by dynamic microindentation technique

Abstract In this study, depth-sensing Vickers indentation tests were conducted on polycrystalline superconductors under different peak load (0.49, 0.73, 0.98, and 1.22 N). The load (P)–penetration depth (h) curves were analyzed in order to evaluate the mechanical characteristics such as microhardness and elastic modulus. It was found that both of these characteristics exhibited significant peak load dependence which suggested a need for calculation of the load-independent hardness and modulus. The load independent hardness (0.88, 0.95, and 1.12 GPa) and modulus (1.98, 3.13, and 3.33 GPa) values were then calculated for YBCO, YBCO + 0.5% ZnO, and YBCO + 1% ZnO, respectively.

[1]  P. Kotru,et al.  Microhardness measurements on single crystals of flux-grown rare earth perovskites (orthoferrites, orthochromites and aluminates) , 1984 .

[2]  O. Uzun,et al.  Hardness evaluation of Al–12Si–0.5Sb melt–spun ribbons , 2003 .

[3]  J. Musil,et al.  Relationships between hardness, Young's modulus and elastic recovery in hard nanocomposite coatings , 2002 .

[4]  I. Low,et al.  Mechanical and fracture properties of epoxy-modified YBaCuO (123) superconductors , 1994 .

[5]  H. Miao,et al.  Load-dependence of Knoop hardness of Al2O3-TiC composites , 2000 .

[6]  B. Surowska,et al.  Analysis of the indentation size effect in the microhardness measurement of some cobalt-based alloys , 2003 .

[7]  B. W. Mott.  Micro-indentation hardness testing , 1956 .

[8]  D. Stone,et al.  Indentation size effect in polycrystalline F.C.C. metals , 2002 .

[9]  Influence of oxygen content and structural defects on low-temperature mechanical properties of high-temperature superconducting single crystals and ceramics , 1997 .

[10]  A. Cavaleiro,et al.  The depth profile analysis of W-Si-N coatings after thermal annealing , 2002 .

[11]  L. B. Harris,et al.  Porosity, density and hardness of Y-Ba-Cu high-Tc superconductors , 1988 .

[12]  H. Miao,et al.  Effect of peak load on the determination of hardness and Young's modulus of hot-pressed Si3N4 by nanoindentation , 2003 .

[13]  Y. Gogotsi,et al.  Microindentation device for in situ study of pressure-induced phase transformations , 1999 .

[14]  G. Pharr,et al.  An improved technique for determining hardness and elastic modulus using load and displacement sensing indentation experiments , 1992 .

[15]  P. Bartos,et al.  Application of depth-sensing microindentation testing to study of interfacial transition zone in reinforced concrete , 2000 .

[16]  Subra Suresh,et al.  DETERMINATION OF ELASTOPLASTIC PROPERTIES BY INSTRUMENTED SHARP INDENTATION , 1999 .

[17]  H. Cimenoglu,et al.  Hardness characterisation of thin Zr(Hf,N) coatings , 2003 .

[18]  J. Gong,et al.  Analysis of the indentation size effect on the apparent hardness for ceramics , 1999 .

[19]  A. Krell,et al.  Depth sensing hardness in sapphire and in sintered sub-μm alumina , 2001 .

[20]  Keshra Sangwal,et al.  Relationship between indentation size effect and material properties in the microhardness measurement of some cobalt-based alloys , 2003 .

[21]  Tom H Johansen.  Flux-pinning-induced stress and magnetostriction in bulk superconductors , 2000 .

[22]  B. Lal,et al.  Mechanical characteristics of melt grown doped KMgF3 crystals , 2003 .