G.A. Rodríguez-Castro

Damage Mechanisms in AISI 304 Borided Steel: Scratch and Daimler-Benz Adhesion Tests

In this study, damage mechanisms in the FeB/Fe2B coatings formed on the surface of AISI 304 steel are determined by adhesion tests. First, the boriding of the AISI 304 steel was carried out through the powder-pack method at 1223 K in the range from 2-10 h of exposure time. After treatment, Berkovich depth-sensing indentation test were conducted; the result showed tensil and compressive residual stresses in the FeB and Fe2B, respectively. The adhesion of borided steels was evaluated by the Daimler-Benz Rockwell-C and scratch test. Based on the scratch tracks, the chipping was the predominant mechanism at 2 and 6 h, with critical loads of 35 and 43 N, respectively; while spalliation was determined at 27 N for 10 h. Also, hertzian and tensil cracks, buckling and compressive delamination were determined in the AISI 304 borided steel by scanning electron microscope.

Effect of Boriding on the Mechanical Properties of AISI 1045 Steel

Some mechanical properties of AISI 1045 borided steels were estimated in the present work. The boriding process was carried out by the powder pack method at 950°C with 8 h of treatment. The fatigue strength on borided notched specimens was evaluated with rotating bending tests (R=1) considering a stress concentration factor (Kt) of 2.53. Likewise, the presence of residual stresses in boride layers was established by the XRD technique. The Daimler-Benz Rockwell C test was used, also, to estimate the strength adhesion of the coated system. The results show a decrease in the fatigue strength of AISI borided steels due to the presence of high porosity in the layers. Finally, the Rockwell-C adhesion test showed no coating failure for the boride layer.

Indentation Technique: Overview and Applications in Food Science

Indentation technique also known as instrumented indentation testing (IIT) has been widely used for characterization of mechanical properties of materials of different nature and different levels. This technique has been mostly used in the field of metallic materials, although in recent years its use has expanded to the biological area, and recently has been also used in the area of food science. The aim of this chapter is to show the general aspects of the indentation technique such as definition, measurement methods and data analysis, measured mechanical parameters, and examples of using the indentation technique in biological materials and specifically in food science. The main contribution of this chapter is to offer the reader a basic understanding of the technique and to show its scope for its possible application in the characterization of food mechanical properties.