The invention discloses a preparation method of a graded porous
nickel-
titanium alloy, and belongs to the technical field of preparation of biomedical materials. The preparation method comprises the steps that Ni
metal powder and Ti
metal powder are weighed according to the composition proportion and then subjected to ball milling mechanical mixing; the
mixed metal powder is divided into a plurality of parts, and the parts and an
ammonium bicarbonate pore forming agent are weighed according to different
porosity ratios and mixed; and after mixing, powder of different compositions is mechanically pressed into a graded block compact, the graded block compact is placed in a
discharge plasma sintering furnace, after a
system is vacuumized to 2 Pa to 6 Pa,
sintering is carried out, the temperature rising rate ranges from 50 min / DEG C to 100 min / DEG C, heat preservation is carried out for 5 min to 10 min under the temperature
ranging from 600 DEG C to 1000 DEG C, furnace cooling is carried out to achieve
room temperature, and a graded porous
nickel-
titanium alloy medical material can be obtained. The part, in contact with the
bone tissue, of the implanted material has high
porosity and the
large aperture, bone cells can be bonded to the surface of the material to grow, and biological locking is formed; and the inner structure is provided with a
dense body high in strength and superelasticity, the material can be matched with the
bone tissue, cooperative deformation is generated, the
stress shielding effect is weakened, and the material can adapt to
stress bearing conditions of bones on different portions. Thus, the biomedical graded porous
nickel-
titanium alloy material prepared through the method can be used as a good bone bearing
orthopedic implant material.