Type of Culminating Activity
Master of Science in Materials Science & Engineering
Materials Science and Engineering
Darryl P. Butt, Ph.D.
The mechanical properties of as-received and irradiated 304 stainless steel (304SS) were evaluated by the shear punch and miniature tensile techniques. A purpose of this study was to evaluate the shear punch technique itself, which is a less developed technique versus miniature tensile testing. This was accomplished in part by comparing yield and ultimate strengths obtained from shear punch and miniature tensile data. The tests were further correlated by evaluating the mechanical properties of aluminum 6061 and Inconels 600 and 718. A linear relationship was observed between the shear strength and tensile strength data, providing a correlation between the two test methods.
The influences, if any, of specimen surface roughness, thickness, and material irradiation history on mechanical properties were evaluated. Through shear punch and miniature tensile testing techniques involving annealed 304 stainless steel, it was demonstrated that surface roughness had no influence on the observed mechanical properties. For T6 aluminum 6061, increased sample thickness lead to decreased ductility while yield and ultimate strengths were similar across the thickness range chosen. The results of specimen surface roughness and thickness experiments show minimal surface preparation is required for accurate strength measurements. The minimum thickness required for shear punch testing is 200 μm.
It is demonstrated that with increased irradiation damage, the strength determined through shear punch testing of 304SS increases. Increased temperature from gamma heating was shown to decrease strength, likely due to annealing at the higher temperatures. A ferroprobe technique was developed to assess whether the changes in strength were due to irradiation damage or thermal gradients or from a martensitic transformation induced during shear punch testing. Similar ferromagnetic measurements at each irradiation and temperature condition suggest a low saturation in the formation of martensite during shear punch testing with increasing irradiation damage.
Rabenberg, Ellen Marie, "Small Specimen Test Techniques for Evaluating Radiation-Induced Changes in Mechanical Properties" (2012). Boise State University Theses and Dissertations. 314.