Ti对CrCoNi中熵合金微观组织和力学性能的影响

The effects of Ti on the phase constituent, microstructure and room-temperature mechanical properties of CrCoNi MEA with various Ti ratios which were prepared by arc melting and drop casting were investigated by using X-ray diffractometer and scanning electron microscope, and the compressive properties and hardness were tested. The results show that the crystalline structure is changed from the initial single face-centered cubic (FCC) structure (x≤0.1) to a duplex FCC plus Ni-Ti-rich phase (0.2≤x≤0.3) and then a third Cr-rich phase (x=0.4) with the Ti ratio increase. The as-cast microstructure is transformed from columnar grains to equiaxed grains at x=0.4. The change of yield stress can be ignored with a few addition of Ti, however the yield strength value is increased remarkably with the presence of the second phases. The maximum value of yield strength is achieved of 1 712.6 MPa at x=0.3, and a good trade-off between yield stress and ductility is acquired at x=0.4.