Accession Number : AD1053767


Title :   Nanocrystalline MAX/Mg Composites with Exceptional Properties


Descriptive Note : Technical Report,10 Oct 2011,09 Oct 2016


Corporate Author : Drexel University Philadelphia United States


Personal Author(s) : Barsoum,Michel W


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1053767.pdf


Report Date : 04 Jan 2017


Pagination or Media Count : 13


Abstract : Understanding the microstructure and mechanical properties of Mg-MAX composites Composites were fabricated by pressureless melt infiltration of Mg and Mg alloys into TiC and Ti2AlC porous preforms. Ti2AlC is a layered machinable ternary carbide (MAX), which is relatively light and stiff. Pure Mg and three Al-containing Mg alloys, AZ31, AZ61 and AZ91 were used as matrices. When the matrix Al content was ? 6 wt.%, the best mechanical properties were achieved for all the composites fabricated. We also studied the effect of reinforcement particle size. For fine-grained reinforcements - 50 vol.% TiC-AZ61 - the elastic modulus was 175+-5 GPa, Vickers hardness was 34+-0.3 GPa, and the ultimate compressive strengths was 1028+-5 MPa. The enhancements in elastic and mechanical properties are attributed to finer grained Mg-matrices, the presence of Al in the matrices which enhances the wetting TiC and Ti2AlC by Mg to create strong interfaces and finer reinforcement particle sizes, that lead to a better mechanical interlocking. In addition, due to Ti2AlC inherent mechanical energy dissipation, damping properties of Mg-Ti2AlC composites were measured to be higher than their TiC reinforcement counterparts. Quite recently we discovered a new micromechanism in the deformation of layered solids; bulk ripplocations, whose existence will upend much of our understanding of the deformation of layered solids.


Descriptors :   composite materials , mechanical properties , microstructure , damping , magnesium alloys , particle size , fabrication , modulus of elasticity , compressive strength , materials processing , neutron diffraction , nanocrystals


Subject Categories : Laminates and Composite Materials


Distribution Statement : APPROVED FOR PUBLIC RELEASE