Abstract: The situation of the research works about the actual mechanical behaviors of metallic parts and constructions (engineering mechanical behaviors of metallic materials) is reviewed. It is proposed to establish an applied science, which is called as “science of engineering mechanical behaviors of metallic materials”, to overcome the limitations of metal science and mechanics in their understanding of different modes of mechanical behavior of metallic parts from their own standpoints. The theoretical basis of this science is a theory, called as “micro-meso-processes theory” , or MMP theory. According to this theory, it is emphasized that any kind of mechanical behavior of metallic parts should be understood comprehensively from its micro-processes (the processes occurring in the surrounding grains and in even wider regions), as well as its microscopical expressions. It is believed that any quantitative theory more exactly reflecting the actual engineering mechanical behaviors can be established only on this basis. Some examples based on our research works about the cleavage and low-temperature brittleness of structural steels, the fatigue source formation and fatigue limit of metals and the super – plasticity of aluminum alloys are given out to make clear the significance and the necessity of establishment of such a science.

Key words: Cleavage and low-temperature brittleness, Fatigue limit, Modeling of mechanical behavior, Super-plasticity