Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Effect of grain size on the fatigue crack growth behavior of 2524-T3 aluminum alloy

Shou W. B., Yi D. Q., Liu H. Q., Tang C., Shen F. H., Wang B.

Archives of Civil and Mechanical Engineering

2016

Vol. 16, no. 3

304--312

2524-T3 aluminum alloy sheets with different grain sizes (13 μm, 59 μm, 178 μm, 355 μm, 126 μm, and 87 μm) were prepared using methods such as rolling and annealing. The microstructures and mechanical properties of the 2524-T3 aluminum alloy sheets were studied using optical microscopy (OM), scanning electron microscopy (SEM), and tensile and fatigue crack growth (FCG) rate tests. The grain size had a significant effect on the fatigue crack growth (FCG) rate. Alloys with grain sizes between 50 and 100 μm exhibited high fatigue crack propagation resistances and the lowest FCG rates (da/dN = 1.05–1.45 × 10−3 mm/cycle at ΔK = 30 MPa m1/2). Microstructural observations revealed that fatigue cracks propagated more tortuously in the alloy with grain sizes within the range of 50–100 μm. This result is attributed to the combined effects of grain boundaries, crack deflection, fracture surface roughness-induced crack closure, and plasticity-induced crack closure.

4,5-Diazafluorene-9-one Acylhydrazones and Their Lead(II) Complexes and the Crystal Structure of Hydrated 4,5-Diazafluorene-9-one 3-Methoxybenzoylhydrazone Supported by Extensive Hydrogen Bonds and Aromatic Ring Stacking Interactions

Xiao W., Lu Z. L., Deng L. Y., Su C. Y., Tong Y. Z., Liu H. Q., Kang B. S.

Polish Journal of Chemistry

2000

Vol. 74, nr 9

1211-1221

4,5-Diazafluorene-9-one acylhydrazone ligands: 4,5-diazafluorene-9-one 3-methoxy benzoylhydrazone (HL1), 4,5-diazafluorene-9-one 2-thiopheneacetylhydrazone (HL2) and 4,5-diazafluorene-9-one isonicotinoylhydrazone (HL3) and their Pb(II) complexes PbL1 2 x 2H2O 1, PbL2(OAc) 2 and PbL3 2 have been prepared and characterized by elemental analyses, molar conductivities, IR and 1H NMR spectroscopy. In all the complexes, the mononegative ligand chelates to the lead ion through the enolic oxygen and the azomethine nitrogen atoms forming a 5-membered chelate ring. An X-ray diffraction analysis on HL1x2H2O shows that it exists in the keto form and each HL1 molecule forms five hydrogen bonds with neighbouring four water molecules through two diazafluorene N, one carbonyl O, one azomethine N and one amide H atom. The hydrogen bonds together with aromatic pi...pi stacking interactions between the phenyl and the diazafluroene ring and between the diazafluorene rings assemble the molecules into a two-dimensional network.