Purpose

Nickel-aluminum bronze (NAB) has been widely used in ship propellers. It is always subjected to local micro-plastic deformation in service environments. This paper aims to study the influence of plastic deformation on the mechanical strength and corrosion resistance of NAB in 3.5 Wt.% NaCl solution.

Design/methodology/approach

Scanning electron microscope and X-ray diffraction were used to analyze the microstructure of NAB alloy with different plastic deformations. Mechanical properties of the sample were measured by tensile experiment, and corrosion behavior was studied by electrochemical measurements and the long-term immersion corrosion test.

Findings

Results showed that the plastic deformation caused lattice distortion but did not change the microstructure of NAB alloy. Microhardness and yield strength of NAB were significantly improved with the increase of deformation. The lattice distortion accelerated the formation of corrosion product film, which made the deformed alloy show a more positive open-circuit potential and an increased Rp. However, during the long-term immersion corrosion, the corrosion resistance of NAB alloys deteriorated with the increase of plastic deformation. This is because larger plastic deformation brought about higher internal stress in corrosion product film, which resulted in the premature peeling of the film and the loss of its protective effect on the alloy substrate.

Originality/value

Tensile plastic deformations were found to cause a decline in the corrosion resistance of NAB. And the mechanism was clarified from the evolution of corrosion products during the corrosion process.

中文翻译：

---

塑性变形对镍铝青铜力学性能和耐腐蚀性能的影响

目的

镍铝青铜（NAB）已广泛用于船舶螺旋桨。它在使用环境中总是受到局部微塑性变形。本文旨在研究塑性变形对 NAB 在 3.5 Wt.% NaCl 溶液中的机械强度和耐腐蚀性能的影响。

设计/方法/方法

采用扫描电镜和X射线衍射仪分析了不同塑性变形的NAB合金的显微组织。通过拉伸实验测量试样的力学性能，通过电化学测量和长期浸入腐蚀试验研究腐蚀行为。

发现

结果表明，塑性变形引起晶格畸变，但并未改变NAB合金的显微组织。NAB的显微硬度和屈服强度随着变形量的增加而显着提高。晶格畸变加速了腐蚀产物膜的形成，使变形合金显示出更正的开路电位和增加的Rp。然而，在长期浸泡腐蚀过程中，NAB合金的耐蚀性随着塑性变形的增加而恶化。这是因为较大的塑性变形导致腐蚀产物膜内应力增大，导致膜过早剥落，失去对合金基体的保护作用。

原创性/价值

发现拉伸塑性变形会导致 NAB 的耐腐蚀性下降。并从腐蚀过程中腐蚀产物的演变过程阐明了机理。