Formation of nanoscale particles and their effect on properties of alloys

Abstract The formation of dispersoids of nanometer size particles and its consequences on the following properties is discussed: precipitation hardening, stabilisation of grain size, stabilisation of austenite against martensitic, and induction of R-phase transformation. Firstly, a survey is given on the aspects which have to be considered for the production of evenly distributed particles in the size range 1–10 nm by precipitation: pre-nucleation clustering, size of the elementary cell, interfacial structure and defects in the matrix lattice, and in situ transformation of metastable phases. Rules are proposed for the production of nano-dispersoids which are valid for all types of alloys. Interaction of dislocations with the dispersed particles leads to a quantitative understanding of the amount and upper limit of precipitation hardening and related properties: work-hardening, localisation of strain, and crack-growth. “Hardening” of ferromagnetic and superconducting materials can be analysed in a similar ...