Nickel aluminum bronze alloys are used in the production of propellers and other components in marine applications. Hot and cold working can improve the mechanical properties of cast nickel aluminum bronze. If wrought alloy is heat-treated, in addition to the elimination of stress, harmful phases are removed and microstructure of the alloy is modified. In this study, the effect of heat treatment on mechanical properties, corrosion behavior and fatigue performance of wrought nickel aluminum bronze was investigated. For this purpose, the as received alloy was subjected to annealing, quenching and ageing treatments at temperatures between 300 ? and 500 ? for 1, 2 and 3 hours. Microstructure of the specimens were observed by optical microscopy and scanning electron microscopy. To study the mechanical properties, hardness and tensile tests were carried out on standard specimens. The corrosion resistance of these samples was evaluated in 3.5% NaCl solution with pH~8 (near the seawater) by potentiodynamic tests. Selected samples, with the best tensile behavior and corrosion resistance, were fatigue tested by four-point rotating bending fatigue machine. The fracture surface of the specimens were also examined by scanning electron microscopy after the corrosion, tensile and fatigue tests. Experimental results showed that the hardness of this alloys increased from annealed condition to as-received, quenched and aged, respectively. The highest corrosion resistance belonged to as-received and annealed conditions, while quenched and aged specimens showed lower corrosion resistance. Tensile properties of the alloy after ageing was reduced; elongation became about 27% and the tensile strength dropped to 215 MPa which was less than the as- received alloy. Fatigue test results showed that the as-received alloy with a higher percentage of spherical ? phase had a better fatigue performance than the annealed condition; the fatigue strength of the as-received specimen was 350 MPa, about 100 MPa higher than that of annealed sample. Microscopic examinations confirmed the results of fatigue tests.
