Grain size refinement

POSTER TITLE Improving the hardness, toughness, wear and creep resistance of NiTiW shape memory thin films by grain size refinement... 

In this case, B4C also undergoes a grain size refinement which is very beneficial for the mechanical properties. In Fig. 55, a micrograph of a reacted TiC-B powder mixture is presented, which still exhibits TiB2 B2C agglomerates of the size of the initial TiC particles. Note that the average particle size of both reaction products is approximately 1 pm. Generally, this reaction can be employed for most of the transition metal boride-boron carbide composites since the borides are usually more stable than the particular carbides [92],... 

This reciprocal salt-couple reaction yields a tremendous grain size refinement since all powder particles are involved in the conversion. After reaction the microstructure is characterized by an average grain size of 1-2 pm, approximately, and the preformation of solid solutions. Thus Eq. (39) has to written more precisely as follows ... 

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