The systems and methods of this patent application are directed to producing a composition of nano-grained NiTi (Ni—nickel, Ti—titanium) alloy for use in producing nano-grained wires. Nano-grained wires, for example, are used to generate medical instruments such as an endodontic instrument. A specific method of producing the nano-grained composition includes preparing a mixture of nickel (Ni) powder and titanium (Ti) powder. The mixture of nickel powder and titanium powder is sintered to produce a nano-grained NiTi alloy. In one embodiment, an endodontic instrument is formed using the nano-grained NiTi alloy and heat-treated.