Page 276 - Fiber Fracture

FRACTURE OF SUPERFINE METALLIC WIRES 259

1.0
LL =13"
0.75
3
Oa5 2

0.25

0 0
3.2 3.0 2.8 2.6 2.4 2.2 2.0
Diameter of drawn wire d (mm)

ci 30 40 50 60
Total reduction rt (%)
Fig. 21. Relationship between the diameter of drawn wire (No. 3) and amount of curl L.

Fig. 22. SEM images of fractured surface in tensile test (No. 4, 4 2.0).

at which the emitted AE energy was high. Under this condition, no filament breaks
were found; however, the core material was constricted. The drawing lengths at which
constriction occurred corresponded to those at which high AE energy was emitted.
The following should be considered in order to detect the generation and develop-
ment of nonuniform deformation and cracks with high sensitivity. AE output is the
accumulation of several signals caused by several factors, including wire defects, as
well as plastic deformation, the lubricant condition and electrical noise. To improve the