The bulk Fe25Co25Ni25Al10Ti15 samples were synthesized via MA followed by SPS. A high-energy planetary ball-milling machine was used to perform the MA process. Blended elemental powders of Fe, Co, Ni, Al, and Ti (purity of >99.7 weight % and particle sizes of ≤45 μm), and tungsten carbide balls were placed in a stainless steel vial. The entire MA process was operated at 300 rpm and protected by argon. First, the powders were subjected to dry milling without a process control agent (PCA) for 45 hours. Four hours of wet milling was conducted using ethanol as PCA following 45 hours of dry milling. Then, the 49-hour as-milled powders were dried. Subsequently, sieved powders with particle sizes of ≤75 μm were obtained after the dried powders passed through a 75-μm sieve. A Dr. Sinter 825 apparatus (Sumitomo Coal Mining Co. Ltd., Japan) was applied to consolidate the sieved powders into bulk samples at 1000°C. During SPS, the vacuum pressure was maintained at <8 Pa, and a constant pressure of 30 MPa was used with a heating rate of 90°C/min. Following SPS, SPS-sintered discs with sizes of Ø20 mm by ~8 mm were obtained, and specimens for subsequent tests were cut by electrical discharge machining.