Quantitative investigation of the precipitation state of microalloyed steels, and its connection with the mechanical properties

The mechanical properties of metallic materials are determined by their microstructure. With microalloyed structural material the precipitation hardening also is a factor that, besides fine grain-, subgrain-, and dislocation hardening, cannot be ignored. Methods have therefore been developed, with which the amount and the size distribution of incoherent precipitations can quantitatively be determined. Here the optical microscope is used for particles with diameters ≥ 0,5 μm, and for smaller ones the electron microscope. In both cases the analysis is made with a half automatic image analyser. As has been demonstrated by an example it is perhaps possible, though there have only been measured incoherent particles, to make quantitative assertions about the coherent precipitation state. (orig.)