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Determination of Plane-Strain Fracture Toughness (K-IC) and The University of Calffomia No.: TilCM-i Lawrence Uvermore o National Laboratory Date: 18 August 1989 *UCCA MOUNTAIN PROJECT V* __,Page: of CONTROLLED COPY NO. _ 102 Subject Determination of Plane-Strain Fracture Toughness (L x)-and;the Threshold Stress Intensity for Stress Corrosion Cracking SCC) Approved by: -1,01,41'4w 4f Technical Area Leader Date Approved by: YP Quality Assurance Manager Date Approved by: PoL Leadr Date YPPro $cq Leater Di PUXR 1 lWASTE sPDC LL 5AU7 (e. 05M% Determination of Plane-Strain Fracture Toughness (ri) and the Threshold Stress Intensity for Stress Corrosion Cracking (Kuc,) aL S. AHLUWALA Science and Engineering Associates Pleasanton, California 94566 J. C. FARMER Lawrence Livermore National Laboratory Livermore, California 94551 Glossary of Terms a crack length, in. acr critical crack length, in. da/dt crack velocity, in./h B thickness, in. C compliance, in./lb E tensile modulus of elasticity, psi f(a/w) mathematical function of a/w. G potential energy release rate, in.lb/in.2 t 2 K - stress intensity factor, general, ksi-in. / K - stress intensity factor, opening mode, ksiin.1/2 Kkc plane-strain fracture toughness, ksi-in. /2 Kb= stress-corrosion cracking threshold stress intensity factor, ksin.1/2 P load, lb Rsc specimen strength ratio W width, in. v Poisson's ratio V crack opening displacement, in. Y constant which is a dimensionless polynomial function in odd half powers of (a/w) from (a/w)1/2 to (a/w)9/2 maximum local stress, ks <iYs - yield strength, ksi Capp applied stress, ksi - fracture stress, ksi surface energy .f I * Contents . Purpo e ..................................................................................................................... 2. Scope ..................................................................................................................... 3. Bacground Theory ........................................................................................................ 3.1 Griffith's Relationship ........................................................................................... 3.2 O row an/Irw in Relationship .................................................................................... 3.3 Energy Release in Terms of Crack Tip Stresses ........................................................... 3.4 Effects of Finite Boundaries ...................................................................................... 3.5 Specimen Size Requirements ............................................... 4. Plane-Strain Fracture Toughness, Testing K 0 . ..................................... 4.1 Introduction ............................................................................................................. 4.2 Sum m ary of Test M ethod .......................................................................................... 4.3 Significance ............................................................................................................. 4A Apparatus .............................................................................................................. 4A.1 List of Equipment and Materials . 4A.2 Special Environmental Conditions . ........................ 4.4.3 Loading....................................................................................................... 4.4A Fixtures ....................................................................................................... 4.4.5 Displacem ent Gage ...................................................................................... 4.4.6 Calibrations ................................................................................................ 4.5 Specimen Size, Configurations, and Preparation ...................................................... 4.5.1 Specim en Size ............................................................................................. 4.5.2 Specim en Configurations .............................................................................. 4.5.3 Specimen Preparation .................................................................................. 4.6 General Procedure .................................................................................................... 4.6.1 N umberof Tests ........................................................................................... 4.6.2 M easurement ............................................................................................... 4.6.3 Loading Rate ............. ; 4.6.4 Test Record ................................................................................................. 4.7 Calculation and Interpretation of Results ................................................................. 4.7.1 Interpretation of Test Record and Calculation of K 0 ..................................... 4.7.2 Fracture Appearance ................................................................................... 4.8 Report ..................................................................................................................... 4.9 Accuracy and Bias .................................................................................................... 4.9.1 Bias ............................................................................................................ 4.9.2 A ccuracy ...................................................................................................... 5. Threshold Stress Intensity for Stress Corrosion Cracking, KLsc ........................................... 5.1 Introduction to K 5.2 Sum mary of Test Method .......................................................................................... 5.3 Apparatus ............................................................................................................... 5.3.1 List of Equipment and Materials .. 53.2 Special Environmental Conditions . ... 5.3.3 Loading. 5.3.4 Fixtures ....................................................................................................... 5.3.5 Displacement Gage. 5.3.6 Test Cell. 5A Specimen Size, Configurations, and Preparation ....................................................... 5.4.1 Specimen Size .............................................................................................. .4.2 Specimen Configuration .............................................................................. 5A.3 Specimen Preparation . ................... ; 5AA. Fatigue Crack Starter Notch .......................... 5.4.5 Fatigue Cracking ......................................................................... 5.5 General Procedure ................................................................................................. 5.5.1 Number of Tests ................ .. 5.5.2 Crack M easurem ent ...................................................................................... 5.5.3 Loading Rate .............................................................................................. 5.5.4 Calibrations . ................. 5.6 Interpretation of Results .......................................................................................... 5.7 Kj/V Calibration5.7 KlV Calbratin ................................................................................................................. 5.8 Experinental Compliance Calibration ..................................................................... 6. Personnel Responsibilities .............................................................................................. 7. Quality Assurance Records ............................................................................................. References ................................................................................................................... Appendix I - Sensitivity Analysis for the Stress Intensity Equation ....... ................ Appendix 2- Sensitivity Analysis for the Strength Ratio Equation ...................................... 1. Purpose This procedure is part of the proposed electrochemical corrosion testing program for the Yucca Mountain Project (YMP) in Nevada. The procedure establishes the general method to be used in evaluating the stress corrosion behavior of the candidate alloys in terms of the embrittlement index, Kxc/Kis=. This ratio shall be used to rank the six possible candidate alloys on the basis of stress corrosion cracking for fabricating the metal containers to be used in disposing of high- level radioactive waste at a repository in Yucca Mountain, Nevada. The six candidate materials are CDA 102 (OFHC copper), CDA 613 (aluminum bronze), CDA 715 (Cu-30Ni), stainless steels Type 304L and 316L, and Alloy 825 [1). This procedure is prepared in accordance with procedures of the Quality Assurance Program Plan to permit acquisition of data that might be applicable to the selection criteria being completed under Activities E 20-15 and E 20-19. 2. Scope This test procedure is divided into three parts. The first part is a brief background theory on plane-strain fracture toughness. The second part covers the determination of plane-strain fracture toughness (KIi) using fatigue-cracked compact tension specimens. Information concerning the recomnendation and requirements for Kle testing are also discussed. The third part covers the determination of the threshold stress intensity for stress corrosion cracking (KL,=) and discusses the additional requirements for its determination. 3. Background Theory The fracture mechanics theory has been reviewed extensively 12-4L so Section 3merely outlines the basic theory of
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