Scanning tunneling microscope observation of the cleavage fracture surfaces of titanium aluminide

We report scanning tunneling microscope images of gold-coated fracture surfaces of soda lime glass and fused silica in the mirror region. The scans show a variety of nanometer scale features that are attributed to fracture phenomena at this scale. We find considerable similarity to the structures observed in regions of extensive crack branching (e.g., “mist”). The density of these features increases as one progresses away from the crack origin toward the mirror-mist boundary. Comparisons are made between soda lime glass and fused silica, revealing differences in the local deformation behavior of these two materials. Self-similarity of the observed structures is probed by measurements of the fractal dimension, Df, of the surfaces created in soda lime glass near the mirror-mist boundary, where we observe 2.17 > Df > 2.40.

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Scanning Tunneling Microscope Observation and Manipulation of DNA and DNA-Related Molecules in Aqueous Condition

Japanese Journal of Applied Physics ◽

10.1143/jjap.37.3838 ◽

1998 ◽

Vol 37 (Part 1, No. 6B) ◽

pp. 3838-3843 ◽

Cited By ~ 2

Author(s):

Tomoko Tano ◽

Masatoshi Tomyo ◽

Hitoshi Tabata ◽

Tomoji Kawai

Keyword(s):

Scanning Tunneling Microscope ◽

Microscope Observation ◽

Scanning Tunneling ◽

Tunneling Microscope

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Scanning tunneling microscope observations of MgO fracture surfaces

Journal of Vacuum Science & Technology A Vacuum Surfaces and Films ◽

10.1116/1.576534 ◽

1990 ◽

Vol 8 (4) ◽

pp. 3470-3478 ◽

Cited By ~ 17

Author(s):

S. C. Langford ◽

Ma Zhenyi ◽

L. C. Jensen ◽

J. T. Dickinson

Keyword(s):

Scanning Tunneling Microscope ◽

Scanning Tunneling ◽

Tunneling Microscope ◽

Fracture Surfaces

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Scanning tunneling microscope observations of metallic glass fracture surfaces

Journal of Materials Research ◽

10.1557/jmr.1993.2543 ◽

1993 ◽

Vol 8 (10) ◽

pp. 2543-2553 ◽

Cited By ~ 14

Author(s):

D.M. Kulawansa ◽

J.T. Dickinson ◽

S.C. Langford ◽

Yoshihisa Watanabe

Keyword(s):

Fracture Surface ◽

Metallic Glass ◽

Metallic Glasses ◽

Scanning Tunneling Microscope ◽

Shear Bands ◽

Scanning Tunneling ◽

Tunneling Microscope ◽

Fracture Surfaces ◽

Glass Fracture ◽

Shear Instabilities

We report scanning tunneling microscope observations of fracture surfaces formed during catastrophic crack growth in three metallic glasses: Ni56Cr18Si22B4, Co69Fe4Ni1Mo2B12Si12, and Fe78B13Si9. Macroscopically, the first two glasses fail along a slip band formed during loading and display a characteristic, μm-scale pattern of vein-like ridges; in contrast, Fe78B13Si9 displays little slip prior to fracture, and its fracture surface shows a μm-scale chevron pattern of steps. STM observations of fracture surfaces of all three materials show nm-scale grooves. The grooves in Co69Fe4Ni1Mo2B12Si12 are especially prominent and display stepped edges which we attribute to the intersection of shear bands with the surface. STM observations of the vein-like features on Ni56Cr18Si22B4 also show stepped edges. We attribute the vein features to the interaction of adjacent crack fingers in which the material between adjacent fingers fails in plane stress. The origin of the grooves is uncertain, but may be due to other shear instabilities along crack fingers.

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