Development of Two New Methods for Estimating Fracture Stress of Fractured Hard or Brittle Materials from Its Fragments (特集硬質材料)

概要

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In the previous studies on the room temperature transverse-rupture strength or fracture stress (σm), fracture toughness (KIC: SEPB method) and fracture origin size (2α) of polycrystalline hard or brittle materials, we have semi-theoretically derived and experimentally verified two equations of σm=ψKICSmf1/2 and σd-1 =σ0-1+Kα1/2: Smf is the total fracture surface area of all fragments of one test piece, σd is the maximum external stress on the fracture origin, etc.. In this study, based on the above each equation, we newly developed two methods for approximately estimating the fracture stress (σm) of the fractured test piece of hard or brittle materials from its fragments, whose fracture load and kind of material are both unknown. Method I: On condition that all the fragments are available, σm can be approximately estimated by use of σm-Smf1/2 correlation lines with a parameter of KIC or equation σm =ψKICSmf1/2 and by measuring Smf and estimating KIC from the correlation line between KIC and KICHV (fracture toughness measured by IF method). Method II: On condition that the fragment including the fracture origin is available, σm can be approximately estimated by use of σd-1-α1/2 correlation lines with a parameter of KIC and by measuring 2α, etc., and by estimating KIC in the same way as in Method I.
社団法人粉体粉末冶金協会の論文
2002-04-15