Zengxi Pan

University of Wollongong | UOW · Faculty of Engineering and Information Sciences

The microstructures, mechanical properties and corrosion behaviors of the ultra-high strength Al–Zn–Mg–Cu-Sc aluminum alloy fabricated by wire-arc additive manufacturing process using a self-prepared 7B55-Sc filler wire were systematically investigated under different heat treatments. The results showed that the microstructures of the as-deposited,...

Monel alloys containing 63Ni–30Cu (wt%) are often used in applications requiring simultaneously high strength and corrosion resistance. Additions of Ti, Al and C to Monel K500 lead to formation of TiC, Ni3Al and Ni3Ti particles, which provide precipitation strengthening effect following heat treatment. The traditional heat treatment schedule includ...

In recent years, Wire Arc Additive Manufacturing (WAAM) has attracted increasing scientific attention. With the rise of Industry 4.0 and smart manufacturing, Digital Twin (DT) has become an emerging technology that is finding increased acceptance in Additive Manufacturing (AM) processes. This paper aims to provide a systematic review of current dev...

Wire-arc additive manufacturing (WAAM) is an arc-based directed energy deposition approach that uses an electrical arc as a source of fusion to melt the wire feedstock and deposit layer by layer. It’s applicable in fabricating large-scale components. At this stage, there are still some issues that need to be researched deeply, such as manufacturing...

The hybridization of additive manufacturing techniques with conventional forming processes offers significant reduction in production cost, time, and material wastage to produce near-net shaped components with refined microstructure and desired properties comparable to its wrought counterparts. In this work, the thermomechanical behavior and micros...

Assembly sequence planning centers around finding an optimal order to assemble parts according to one or several operational objectives, while subjected to various constraints. This paper presents a new method to extract data from the assembly model and represent stability constraints in matrix form to support mathematical operations. Unlike previo...

Ultra-high strength 7xxx series aluminum alloys are widely used in aerospace applications due to their exceptional high specific strength. Wire + Arc Additive Manufacturing (WAAM) is a combination of arc and wire feeding additive manufacturing technology including either the gas tungsten arc (GTA) or the gas metal arc (GMA) process. And this techno...

Lightweight aluminum alloy lattice structures have broad application prospects in energy absorption, heat insulation, vibration isolation, etc. Additive manufacturing (AM) has been increasingly applied to fabricating lattice structures due to its efficient and flexible technical characteristics. Wire arc additive manufacturing (WAAM), featuring hig...

A new structure with nickel-based Hastelloy C276 alloy cladding on creep resistant steel P91 was developed in this study for nuclear applications. The microstructure, including precipitation and grain size, boundaries, orientation and hardness distribution of cladding structures with/without post heat treatment were explored using a range of micros...

WAAM has been proven a promising alternative to fabricate medium and large scale metal parts with a high depositing rate and automation level. However, the production quality may deteriorate due to the poor deposited layer surface quality. In this paper, a laser sensor based surface roughness measuring method was developed for WAAM. To improve the...

An equiatomic CoCrFeNiMn High Entropy Alloy (HEA) was in-situ deposited by the powder-bed arc additive manufacturing (PBAAM) process for the first time. Comparative research was conducted on the evolution of phase, crystallographic orientation, dislocation morphology, precipitation, and mechanical performance with the accumulation of inter-layer re...

In this study, microstructure and mechanical properties of wire arc additively manufactured Ti6Al4V alloy with/without magnetic arc oscillation were investigated by means of optical microscopy (OM), electron backscatter diffraction (EBSD), X-ray diffraction (XRD), scanning electron microscopy (SEM), and standard tensile testing. The results show th...

Rapid developments in artificial intelligence and image processing have presented many new opportunities for defect detection in manufacturing processes. In this work, an intelligent image processing system has been developed to monitor inter-layer deposition quality during a wire arc additive manufacturing (WAAM) process. This system reveals the f...

Wire-arc additive manufacturing (WAAM) technology has been widely recognized as a promising alternative for fabricating large-scale components, due to its advantages of high deposition rate and high material utilization rate. However, some anomalies may occur during the deposition process, such as humping, spattering, robot suspend, pores, cracking...

Improving the geometric accuracy of the deposited component is essential for the wider adoption of wire arc additive manufacturing (WAAM) in industries. This paper introduces an online layer-by-layer controller that operates robustly under various welding conditions to improve the deposition accuracy of the WAAM process. Two control strategies are...

In recent years, twin wire-arc additive manufacturing (T-WAAM) technique has been considered as a promising method of fabricating and shaping titanium aluminide components with high efficiency and low cost. However, excessive thermal input of the non-consumable tungsten electrode arc deposition induces significant residual stresses in the buildup c...

The development of high-entropy alloys (HEAs) based on the novel alloying concept of multi-principal components presents opportunities for achieving new materials with desired properties for increasingly demanding applications. In this study, a low neutron cross-section FeCrVTiNi-based HEA was developed for potential nuclear applications. A face-ce...

This research work investigated the effects of standard solution-annealed (SA) treatment on microstructure and chemical characteristics of Inconel 718 (IN718) superalloys fabricated using tungsten inert gas welding based wire-arc additive manufacturing (WAAM) process. A commercial wrought IN718 product was also studied for comparison. It was observ...

Wire and arc additive manufacturing(WAAM) is a promising method for directly manufacturing parts with complex shapes. However, the accuracy of the existing welding parameter planning methods would dramatically decrease when bead geometry changes dynamically due to the long-term dependence, strong coupling, and hysteresis properties of the WAAM proc...

Wire Arc Additive Manufacturing (WAAM) is a promising manufacturing technology that has been used to build medium to larger-sized components. The recent progress of Artificial Intelligence (AI) technology has led to Machine Learning (ML) algorithms being widely implemented for modeling, control, monitoring, and simulation processes in WAAM. However...

Relatively high heat input and heat accumulation are treated as critical challenges to affect the qualities and performances of components fabricated by wire arc additive manufacturing (WAAM). In this study, various heat inputs, namely 276, 552 and 828 J/mm, were performed to fabricate three thin-wall Inconel 625 structures by cold metal transfer (...

Rapid developments in artificial intelligence and image processing have presented many new opportunities for defect detection in manufacturing processes. In this work, an intelligent image processing system has been developed to monitor inter-layer deposition quality during a Wire Arc Additive Manufacturing (WAAM) process. Information produced from...

Wire-arc additive manufacturing (WAAM) technology has been widely recognized as a promising alternative for fabricating large-scale components, due to its advantages of high deposition rate and high material utilization rate. However, some anomalies may occur during the deposition process, such as humping, spattering, and robot suspend. this study...

In more recent times, research on various aspects of the Wire Arc Additive Manufacturing (WAAM) process has been conducted, and efforts into monitoring the WAAM process for defect identification have increased. Rapid and reliable monitoring of the WAAM process is a key development for the technology as a whole, as it will enable components produced...

Monel alloys containing 63Ni-30Cu-2.0Mn-2.0Fe-AlTiC (wt. %) are often used for manufacturing of machine parts in marine, chemical, and oil extraction industries. Despite excellent corrosion resistance and mechanical properties, Monel components may fail via wear, which is enhanced in corrosive environment. Heavy components working under high loads...

Wire arc additive manufacturing (WAAM) is well suited for the manufacture of sizeable metallic workpieces featuring medium-to-high geometrical complexity due to its high deposition rate, low processing conditions limit, and environmental friendliness. To enhance the current capability of the WAAM process for fabricating structures with complex geom...

With the increasing demand for high productivity and low cost, the advanced manufacturing system has become more complex. It is challenging to develop an advanced manufacturing system by engineers or researchers from manufacturing engineering disciplines. To combine knowledge and skills from two or more disciplines, interdisciplinary engineering (I...

To meet lightweight demands, complex support or near-net shaped structures are increasingly applied in modern industry sectors. Wire arc additive manufacturing (WAAM) of these structures requires a profound knowledge of the interactions between material properties, welding process and mechatronic engineering. This study shows a new WAAM strategy, t...

The wire arc additive manufacturing (WAAM) is one of the advanced manufacturing processes to fabricate full-density 3D Inconel 718 (IN718) metal parts in an open freeform environment. Thus, there is no size restriction of the fabricated parts using this process which is suitable for industry-led medium to large production supply chain. So far, the...

Fe3Al based alloys have been continuously attractive to the fossil energy industry due to the excellent high temperature oxidation resistance and strength, light weight and low materials cost. In recent years, to overcome the fabrication difficulty of Fe3Al based alloys and reduce the room temperature induced high manufacturing cost, the twin wire-...

Aluminum alloy lattice structures featuring superior energy absorption, lightweight, and high strength-weight ratio, are achievable using Additive Manufacturing (AM) technology such as selective laser sintering. However, the size of the structure is limited, and the cost is relatively high. As a free-form rapid prototyping technology, Wire Arc Addi...

Wire arc additive manufacturing (WAAM) is a promising alternative to laser-powder based additive manufacturing for fabricating large metallic components due to its high productivity and low cost. The high heat input of the arc welding process causes significant thermal stresses resulting in large distortion of the components. Finite element methods...

This work investigated the high-temperature oxidation kinetics and evolution of oxide phases of as-fabricated (AF) and heat-treated (HT) Inconel 718 alloys in air fabricated by the wire-arc additive manufacturing process. The results showed that the oxidation kinetics of all samples followed the parabolic time dependence. The microstructural study...

Wire Arc Additive Manufacturing (WAAM) of large thin-walled aluminium structures in the aerospace field has significant advantages over traditional subtractive approaches. The technique is based on arc welding and wire filler material, and the thin-walled structures are built up layer-by-layer. However, for the parts with sharp corners, the shape c...

As promising technology with low requirements and high depositing efficiency, Wire Arc Additive Manufacturing (WAAM) can significantly reduce the repair cost and improve the formation quality of molds. To further improve the accuracy of WAAM in repairing molds, the point cloud model that expresses the spatial distribution and surface characteristic...

Additive manufacturing based on robotic welding is used for the manufacture of metal parts by applying an arc as a heat source and wire as feedstock. The process is known as wire arc additive manufacturing (WAAM). However, the current WAAM process has a limitation in fabricating block structure components with high geometry accuracy and consistent...

Wire Arc Additive Manufacturing (WAAM) has revolutionized the manufacturing paradigm for fabricating medium to large scale metallic parts featuring high buy-to-fly ratios such as aerospace components. As a promising technology for the manufacturing industry, it is necessary to develop an automated WAAM system with high efficiency and low labour cos...

Wire Arc Additive Manufacturing (WAAM) is well suited for the manufacture of sizeable metallic workpieces featuring medium-to-high geometrical complexity due to its high deposition rate, low processing conditions limit, and environmental friendliness. To enhance the current capability of the WAAM process for fabricating structures with complex geom...

Functionally graded material has been increasingly attractive due to the locally designed and optimized material properties. In the present paper, to achieve high thermal lattice structural stability and high corrosion resistance in each side of one bulk material, an Fe3Ni–FeNi compositionally graded material (FGM) bulk sample has been fabricated u...

Weld bead geometry features (WBGFs) such as the bead width, height, area, and center of gravity are the common factors for weighing welding quality control. The effective modeling of these WBGFs contributes to implementing timely decision making of welding process parameters to improve welding quality and enhance automatic levels. In this work, a d...

A new Powder-bed Arc Additive Manufacturing (PAAM) processing which includes on-line remelting of deposited material has been developed for the manufacturing of high entropy alloys (HEAs) based on an existing AlCoCrFeNi2.1 pseudo-eutectic system. The remelting process is typically applied in the arc melting process to improve the homogeneity of pre...

As a new emerging technology, wire arc additive manufacturing (WAAM) has attracted extensive interests from both academia and industry during recent years. WAAM uses welding arc as an energy source to fuse metal wire and deposit layer by layer, which provides the advantages of freeform deposition. In order to improve its manufacture precision, stab...

Wire arc additive manufacturing technology (WAAM) has become a very promising alternative to high-value large metal components in many manufacturing industries. Due to its long process cycle time and arc-based deposition, defect monitoring, process stability and control are critical for the WAAM system to be used in the industry. Although major pro...

Wire arc additive manufacturing (WAAM) is an emerging technology in the manufacturing industry, which uses a welding arc as an energy source to fuse metal wire and deposit layer by layer. In order to promote its manufacture precision, stability, and repeatability, it’s crucial to develop a feedback control strategy for WAAM. This research implement...

Magnetic Arc Oscillation was applied during the construction of single-pass multi-layer walls of low carbon steel and Ti6Al4V by the Gas Tungsten Arc Welding-based Wire and Arc Additive Manufacturing process, and the influence on the geometry and the process stability was evaluated. The geometric features were assessed using transverse section macr...

FeNi intermetallic has been continuously attractive due to the appreciable magneto-crystalline anisotropy and high saturation magnetization in the nominally-equiatomic chemically ordered L10 structure. In the present research, the bulk FeNi alloy is successfully fabricated using an innovative wire-arca additive manufacturing process, which is also...

Wire arc additive manufacturing (WAAM) is a Direct Energy Deposition (DED) technology, which utilize electrical arc as heat source to deposit metal material bead by bead to make up the final component. However, issues like the lack of assurance in accuracy, repeatability and stability hinder the further application in industry. Therefore, a Model F...

As an advanced and highly efficient welding method, Keyhole Tungsten Inert Gas (keyhole TIG) welding has drawn wide interests from the manufacturing industry. In order to improve its manufacturing quality and automation level, it’s necessary to develop an online monitoring system for the keyhole TIG welding process. This study developed a visual mo...

The evolution of microstructure, phase transformation, nanohardness, and pseudoelasticity of a Ni-rich NiTi alloy in-situ processed by wire arc additive manufacturing (WAAM) with different deposition current was assessed. As the deposition current increased, the size of the B2 grains and Ni4Ti3 precipitates coarsened and the characteristic phase tr...

In the present research an Fe–Fe3Ni functionally graded material has been fabricated using an innovative wire-arc additive manufacturing process. Considering the residual bcc-α-Fe in the bulk material, a homogenization heat treatment is conducted to the as-fabricated alloy to transform the residual bcc lattice into fcc structure. During the entire...

In the present research, to further reduce the fabrication and forming cost of NiTi alloy, an innovative wire-arc additive manufacturing process (WAAM), which is simultaneously an in-situ alloying process, has been applied to fabricate polycrystalline Ni53Ti47. The as-fabricated alloy is subsequently subjected to a necessary post-production anneali...

The present study centres on the effect of post-weld heat treatment (PWHT) on microstructure and mechanical properties of the deep penetration keyhole Tungsten Inert Gas (K-TIG) welded dissimilar joint between creep strength enhanced ferritic (CSEF) steel and austenitic stainless steel (ASS). The as-received normalized and tempered CSEF steel was j...

Wire Arc Additive Manufacturing (WAAM) is a promising technology for fabricating medium to large scale metallic parts with excellent productivity and flexibility. Due to the positional capability of some welding processes, WAAM is able to deposit parts with overhanging features in an arbitrary direction without additional support structures. The di...

Robotic wire arc additive manufacturing (WAAM) technology has been widely employed to fabricate medium to large scale metallic components. It has the advantages of high deposition rates and low cost. Ideally, the deposition process is carried out in a flat position. The build direction is vertically upward and perpendicular to a horizontal worktabl...

Ni-rich NiTi alloys were deposited using the in-situ alloying wire arc additive manufacturing (WAAM) method, with varying deposition currents from 80 A to 120 A. The effects of deposition current on the crystal orientation, precipitation, phase transformation and mechanical properties of the WAAM-deposited NiTi alloys were investigated. The results...

Realizing improved strength in composite metallic materials remains a challenge using conventional welding and joining systems due to the generation and development of brittle intermetallic compounds caused by complex thermal profiles during solidification. Here, wire arc additive manufacturing (WAAM) process was used to fabricate a steel-nickel st...

In this paper, active interpass cooling was implemented in the wire arc additive manufacturing (WAAM) of Ti6Al4V parts. In comparison to standard WAAM processed material, the introduced process contributes to improved microhardness and enhanced mechanical strength due to its ability to produce more fine-grained acicular α and finer α lamellae, offe...

In this study, the wire arc additive manufacturing (WAAM) technique was utilized to deposit a protective NiTi layer on a Ti6Al4V substrate through in-situ alloying of separate pure Ni and Ti wires to enhance the surface mechanical properties. The influence of arc current on the microstructure, phase formation, microhardness transition and dry-wear...

Cryogenic treatment is an effective route to obtain fine grained microstructure in materials. In this work, the effect of deep cryogenic treatment (DCT) on the microstructural evolution and mechanical properties of a copper-aluminum-silicon (Cu–Al–Si) alloy deposited by cold metal transfer (CMT) technology was investigated. Copper-rich Cu–Al–Si all...

An initial attempt has been made to fabricate titanium iron (TiFe) intermetallic compound (IMC) by the wire arc additive manufacturing process which is cheap, fast, and has the ability to produce near-net shape product. The microstructural analysis confirms that TiFe IMC has been successfully fabricated and the wall build-up constitutes of TiFe IMC...

Keyhole mode Tungsten Inert Gas (K-TIG) welding is a novel advanced deep penetration welding technology which provides an alternative to high power density welding in terms of achieving keyhole mode welding. In order to facilitate welding procedure optimisation in this newly developed welding technology, the relationship among welding parameters, w...