Study of the rol of transition metal elements in the mechanical properties and glass forming ability of amorphous steels

Amorphous steels are a particular class of Fe-based bulk metallic glasses (BMGs) with potential use in structural applications due to its interesting mechanical properties. Recently, it has been shown how the partial substitution of Fe by a transition metal (TM) element (Mo) can enhance the glass forming ability (GFA) of the alloy, thus allowing the production of bulk pieces that can be used in industrial applications. The TM element must be alloyed in the optimal proportion in order to induce the formation of several local atomic environments in the amorphous matrix that compete between them, thus preventing the nucleation of crystalline domains and stabilizing the amorphous structure. In the present work, the mechanical properties of several compositions of amorphous steels will be characterized. In particular, the effect of substituting Fe by two TM elements (Mo and Cr) will be studied and compared with the results obtained previously by means of Mössbauer Spectroscopy, a technique that provides information about the local order of the amorphous matrix surrounding the Fe atoms. The research work will consist of four stages: 1)Mechanical characterization of three amorphous steels with varying concentrations of Mo and with different relaxation states. The applicant will learn to use a Dynamo-Mechanical analyzer to perform the stress-strain curves of the materials. 2)Synthesis and characterization of amorphous steels with varying concentrations of Cr. The applicant will learn several synthesis techniques such as arc-melting and melt-spinner quenching. 3)Mechanical characterization of these new compositions and correlation between the mechanical properties of the studied samples and their local structure determined by Mössbauer Spectroscopy. 4)Determination of the rol of TM elements in the local structure and the macroscopic properties of amorphous steels