Fabrication of crystallized Ti_(70)Nb_(7.8)Cu_(8.4)Ni(7.2)Al_(6.6) composites by spark plasma sintering or crystallization of amorphous phase

The Ti-based amorphous alloy powders without or with 2%(volume fraction,%) B4C were synthesized by mechanical alloying,and subsequently the powders were consolidated into crystallized Ti70Nb7.8Cu8.4Ni7.2Al6.6 ultrafine/fine-grained composites without or with(TiB+TiC) phases by spark plasma sintering and crystallization of amorphous phase.The synthesized powders and the consolidated ultrafine/fine-grained composites were examined by X-ray diffractometry(XRD),differential scanning calorimetry(DSC),scanning electron microscopy(SEM) and universal materials tester.The results show that,after a milling time of 80 h,the synthesized powders consist of amorphous phase with predominant volume fraction.The addition of B4C particles has an obvious impact on the glass transition temperature,crystallization temperature and crystallization enthalpy for the synthesized powders.In addition,the microhardnesses of the consolidated composites without or with 2% B4C are 5.47 and 5.33 GPa,respectively.Meanwhile,the consolidated Ti70Nb7.8Cu8.4Ni7.2Al6.6 composite by heating to 1 223 K at 50 K/min and holding for 10 min has a high fracture strength of 2 098 MPa and a fracture strain of 11.5%.