Nickel-Aluminum Bronze (NAB) Review: Additive Manufacturing and Weldability
Abstract
Nickel-aluminum bronze (NAB) alloys are commonly used for marine applications such as propellers by the U.S. Navy. These NAB components are conventionally manufactured using casting techniques, but recent interest has shifted to the possibility of additive manufacturing (AM) processes. The following literature review discusses the microstructural evolution of (nominally) Cu-9Al-5Ni-5Fe-1Mn NAB alloys in the cast, wrought, arc-welded, and laser-welded conditions. NAB alloys exhibit a complex microstructure, consisting of a mixture of four . precipitates distributed in an a or martensitic matrix. The size, morphology, and distribution of these phases are sensitive to changes in cooling rate and thermal history such as those imposed by AM and welding. Although the microstructure is well documented under casting conditions, no continuous cooling diagrams have been developed to describe phase transformations under arc and laser processing conditions for NAB. As such, this review investigates recent reports related to arc- and laser-based additive manufacturing processes and the associated microstructures and properties. Studies have reported additively manufactured NAB alloys with improved properties compared to cast material, due in part to the difference in microstructure. At moderate cooling rates such as those associated with arc-based processing, the microstructure consists of Widmansttten a and various . phases, which become more refined with increasing cooling rate. This leads to an improvement in the tensile properties of wire-arc direct energy deposited NAB, with >17 increase in yield strength and >90 increase in ductility when compared to cast material. At rapid cooling rates representative of laser-based processing, the microstructure consists primarily of a twin-related martensite with nanoscale . phases. This leads to a significant increase in yield strength (>60-100 ) at the expense of ductility (<-30 ) when compared to cast material.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2021
- Accession Number
- AD1147115
Entities
People
- Charles R. Fisher
- Jennifer K. Semple
- Sean M. Orzolek
Organizations
- Naval Surface Warfare Center