THE SEPARATION OF CORROSION AND STRESS EFFECTS IN STRESS CORROSION TESTING

A STRESS CORROSION TESTING METHOD WHICH ALLOWS THE SEPARATION OF PURE CORROSION EFFECTS FROM THOSE OF TRUE STRESS CORROSION IS PROPOSED. BY APPLYING STRESS AFTER VARYING AMOUNTS OF CORROSION WITHOUT STRESS (PRECORROSION) IT IS POSSIBLE TO DETERMINE QUANTITATIVELY WHAT FRACTION OF THE TOTAL TIME TO FAILURE AS MEASURED IN A NORMAL STRESS CORROSION PROCESS (GREATER DAMAGE WHEN STRESS AND CORROSION ACT TOGETHER THAN WHEN EACH ACTS SEPARATELY). A PRECORROSION SUSCEPTIBILITY INDEX (PSI) IS DEFINED WHICH GIVES A MEASURE OF THE IMPORTANCE OF STRESS IN THE STRESS CORROSION PROCESS. THIS INDEX VARIES FROM UNITY, FOR THE CASE WHERE PRECORROSION IS JUST AS DAMAGING AS CORROSION UNDER STRESS, TO ZERO, FOR THE CASE WHERE CORROSION WITHOUT STRESS CAUSES NO DAMAGE AT ALL. EXAMPLES OF THE APPLICATION OF THIS TESTING METHOD TO BOTH ALUMINUM AND TITANIUM ALLOYS ARE GIVEN, AND IT IS SHOWN THAT PSI VALUES RANGING FROM UNITY TO NEARLY ZERO ARE FOUND. FURTHERMORE, DIFFERENT PSI VALUES MAY BE OBTAINED FOR DIFFERENT STAGES OF THE TOTAL FAILURE PROCESS. THE USE OF THIS TECHNIQUE FOR DISTINGUISHING THE MAIN FEATURES OF THE MECHANISM OF THE OVER-ALL FAILURE PROCESS IS DISCUSSED.

• Supplemental Notes:
  • Vol 9, No 12, PP 29-31, 54-55, 4 FIG, 1 TAB, 11 REF
• Authors:
  • Cocks, F H
• Publication Date: 1969-12

Media Info

• Serial:
  • Materials Research and Standards
  • Publisher: American Society for Testing and Materials (ASTM)

Subject/Index Terms

• TRT Terms: Aluminum alloys; Corrosion; Failure; Stress corrosion; Stresses; Test procedures; Titanium alloys
• Subject Areas: Geotechnology; Highways; Materials;

Filing Info

• Accession Number: 00216930
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 20 1970 12:00AM