Development of Two New Methods for Estimating Fracture Stress of Fractured Hard or Brittle Materials from Its Fragments (特集 硬質材料) Development of Two New Methods for Estimating Fracture Stress of Fractured Hard or Brittle Materials from Its Fragments
Access this Article
Search this Article
Author(s)
Abstract
In the previous studies on the room temperature transverserupture strength or fracture stress (σ<SUB>m</SUB>), fracture toughness (K<SUB>IC</SUB>: SEPB method) and fracture origin size (2α) of polycrystalline hard or brittle materials, we have semitheoretically derived and experimentally verified two equations of σ<SUB>m</SUB>=ψK<SUB>IC</SUB>S<SUB>mf</SUB><SUP>1/2</SUP> and σ<SUB>d</SUB><SUP>1</SUP> =σ<SUB>0</SUB><SUP>1</SUP>+Kα<SUP>1/2</SUP>: S<SUB>mf</SUB> is the total fracture surface area of all fragments of one test piece, σ<SUB>d</SUB> is the maximum external stress on the fracture origin, etc..<BR>In this study, based on the above each equation, we newly developed two methods for approximately estimating the fracture stress (σ<SUB>m</SUB>) 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, σ<SUB>m</SUB> can be approximately estimated by use of σ<SUB>m</SUB>S<SUB>mf</SUB><SUP>1/2</SUP> correlation lines with a parameter of K<SUB>IC</SUB> or equation σ<SUB>m</SUB> =ψK<SUB>IC</SUB>S<SUB>mf</SUB><SUP>1/2</SUP> and by measuring S<SUB>mf</SUB> and estimating K<SUB>IC</SUB> from the correlation line between K<SUB>IC</SUB> and K<SUB>IC</SUB><SUP>HV</SUP> (fracture toughness measured by IF method). Method II: On condition that the fragment including the fracture origin is available, σ<SUB>m</SUB> can be approximately estimated by use of σ<SUB>d</SUB><SUP>1</SUP>α<SUP>1/2</SUP> correlation lines with a parameter of K<SUB>IC</SUB> and by measuring 2α, etc., and by estimating K<SUB>IC</SUB> in the same way as in Method I.
Journal

 Journal of the Japan Society of Powder and Powder Metallurgy

Journal of the Japan Society of Powder and Powder Metallurgy 49(4), 294298, 20020415
Japan Society of Powder and Powder Metallurgy