Surface Crack in Flexure

FN ISO (2003) 18756. Fine ceramics (Advanced Ceramics, Advanced Tedmical Ceramics) - Determination of Fracture Foulness of Monolithic Ceramics at Room Temperature by the Surface Crack in Flexure (SCF) Method, International Organization for Standardization. 

R. Moon, K. Bowman, K. Trumble, J. Roedel, Comparison of R curves from single edge V notch beam (SEAfB) and surface crack in flexure(SCF) fracture toughness test methods on multilayered alumina zirconia composites, J. Am. Ceram. Soc. 83 [2] 445 47 (2000)... 

G. D. Quinn and J. A. Salem, Effect of Lateral Cracks Upon Fracture Toughness Determined by the Surface Crack in Flexure Method, J. Am. Ceram. Soc., 85 (4) 873 80 (2002). 

K. Yasuda, T. Taguchi, J. Tatami, and Y. Matsuo, Estimation of Short Crack R Curves of Polycrystalline Ceramics by Surface Crack in Flexure Method, pp. 115 120 in Improved Ceramics Through New Measurements, Processing and Staruiards, Ceramic Transactions, vol. 133, (2002). 

G.D. Quinn, R.J. Gettings, and J.J. Kubler, Fractography and the Surface Crack in Flexure (SCF) Method for Evaluating Fracture Toughness of Ceramics, Fractography of Glasses and Ceramics, Ceramic Transactions, Vol. 64, American Ceramic Society, Westerville, OH, 1996, pp. 107 144. G.D. Quinn and J.A. Salem, Effect of Lateral Cracks on Fracture Toughness Determined by the Surface Crack in Flexure Method, J. Am. Ceram. Soc., 85 [4] 873 880 (2002). 

ASTM C 1421 for advanced ceramics includes three related test method procedures as illustrated in Figure 2. The three methods are the surface crack in flexure (SCF), precracked beam (PB) [also known as single-edge precracked beam (SEPB)], and chevron notch in bending (CNB) methods. The content and development of C 1421 and its precursor, ASTM PS 070-97 are documented elsewhere [2,3,4,5]. The SRM may also be used with three ISO standard test methods that are under development in Technical Committee TC 206, based on the SEPB, SCF, and CNB methods. It may also be used with a draft CEN standard that features SCF, CNB, SEPB, and single edge-V-notched beam methods, as well as JIS R 1607 which has the SEPB method. "... 

Technical Working Area 3, Structural Ceramics, has conducted thirteen major round robins over the course of 13 years, including five round robins and 4,500 experiments on fracture toughness alone.The 1993 to 1994 round robin featured the surface crack in flexure (SCF) method. Twenty laboratories around the world obtained very consistent results on test specimens from a single billet (designated E ) of the NC... 

One of the advantages of the three methods in C 1421 is that they all use a simple bend bar. Each 3 mm x 4 mm x 45 mm to 47 mm bar test specimen was prepared in accordance with the generic ( standard ) preparation procedure specified in the flexural strength standards MIL STD 1942 MR," ASTM C 1161," and ISO 14704. ° One 4 mm wide face was finished with a 900 grit wheel (finer than is normally required) to produce a flat and smooth surface for the Knoop indentation in the SCF test method. The four long edges of the test specimens were chamfered in accordance with requirements for the surface crack in flexure (SCF) and precracked beam (SEPB) test methods. 

G. D. Quinn, VAMAS After Twelve, Bulletin of the American Ceramic Society, 78 (7) 78 83 (1999). G. D. Quinn, J. J. Kiibler, and R. J. Gettings, Fracture Toughness of Advanced Ceramics by the Surface Crack in Flexure (SCF) Method A VAMAS Round Robin, VAMAS Technical Report 17, National Institute of Standards and Technology, Gaithersburg, MD 20899, June, 1994. 

---