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Lecture

WEB Property changes in steels prepared for in-situ SEM testing using gold remodeling

Tuesday (22.09.2020)
14:30 - 14:45 Z: Special Symposia I
Part of:


The gold remodeling technique offers a fine speckled pattern of finely dispersed gold particles on the sample surface, providing excellent contrast and spatial resolution for digital image correlation (DIC) on in-situ testing samples in the scanning electron microscope (SEM). For all kind of mechanical testing the sample should be representative for the given material in order to give reliable results. To obtain the speckled pattern on the in-situ tensile test samples, the specimens are first coated with a continuous gold layer. Secondly the gold layer is remodeled by keeping the specimen at 180⁰C in a styrene atmosphere for 96 hours. Samples of different steels were tested both in the as received condition and heat treatment in a way similar to the gold remodeling. The heat treatment at relatively low temperature does not affect the properties of a ferritic-pearlitic carbon steel. However, when looking at dual phase steels containing martensite and ferrite, the yield point increases significantly after the heat treatment. At 180⁰C the carbon gets time to redistribute in the martensitic microstructure. The heat treatment is, however, only found to have a strong effect on the yield strength as the work hardening behavior is similar for the as received and heat treated samples. The gold remodeling technique should, hence, be used with the thought in mind, that microstructural changes may occur leaving the results non-representative for the material.


 

Speaker:
Ida Westermann
Norwegian University of Science and Technology - NTNU
Additional Authors:
  • Dr. Christian Oen Paulsen
    NTNU
  • Prof. Tore Børvik
    NTNU