Constrained groove pressing (CGP) is one of the best available sheet material processing technique for grain refinement and improving material properties without changing the original dimensions of the specimen. In this work, CGP is successfully performed on 10 mm thick mill-annealed Ti6Al4V plates at a temperature of 550 °C up to three passes. Microstructure studies reveal that grain size decreased

Previous studies have shown that sharp physical and chemical changes may induce the formation of swirl-like reaction phases in the ultrasonic spot welding (USW) of different materials. However, the mechanisms have not been well understood. In particular, swirl-like structures have seldom been discovered or discussed in the USW of Cu/Sn. In this study, swirl-like phases were observed in the USW of a

Additive manufacturing (AM) provides a higher degree-of-freedom manufacturing process for high-mix low-volume manufacturing. However, the as-built surface quality by AM processes is generally inferior to that fabricated by conventional subtractive manufacturing and the machinability investigation for post-processing of additively manufactured (AMed) parts is insufficient. In this paper, milling experiments

A novel composited process including solution treatment-hot gas forming and stress relaxation aging is proposed in this paper to form titanium alloys component with high precision and improved strength simultaneously. Firstly, solution and aging treatments were carried out to study the effects of processing parameters on microstructure and properties. Secondly, uniaxial tensile tests at solution temperature

Highly finished copper surface without any appreciable residual stress is in high demand in electronics, space, and optical industries. Conventional finishing processes are not suitable for the finishing of copper owing to its extremely lower hardness. In the present study, wheel based magnetorheological finishing (MRF) process is used to attain nanolevel surface roughness of oxygen-free high conductivity

A ferrite-austenite 12CrNi2 alloy steel additively manufactured by laser melting deposition (LMD) has been treated by various quenching methods, including direct quenching (DQ), inter-critical quenching (IQ) and step quenching (SQ), respectively, to form the martensite-ferrite dual-phase steel with a similar major volume fraction (62 vol.%) but different grain sizes and lath substructures of martensite

Ultrasonic metal forming technology has a great potential for highly productive manufacture of miniature parts. Extremely high plasticity can be achieved under the condition of ultrasonic impact loading of the small-height and thin samples (the so-called “ultrasonic dynamic impact effect”). Despite this, the wide use of ultrasonic micro-forming processes is restricted with some technical challenges

Three nitrogen-rich welding wires with nitrogen content of 0.15 %, 0.6 % and 0.9 % for high nitrogen stainless steel welding were developed by a modified Schaeffler diagram and equilibrium phase diagram calculation. The effect of the chemical compositions especially the nitrogen on the weld defects, element distribution, microstructure, mechanical properties and droplet transfer were studied to evaluate

Components fabricated by the deposition and solidification of molten droplets have the common defect of rough surface, which are mainly caused by the poor bonding and inadequate evolution of the interface. To address such a problem, the pileup process of vertical column by successive droplets was simulated under an axisymmetric system, where the evolution of interface was captured by Front Tracking

The evolution of crystallographic texture during the thermo-mechanical processing of aluminium sheet is accompanied by the development of plastic anisotropy and, most notably, the well-known earing phenomenon. In the present paper we analyse the formation of texture and earing properties in sheets of the Al-Mg alloy AA 5050A (ISO AlMg1.5(D)) along a process route resulting in temper H16 after cold

Vibration-assisted machining (VAM) is implemented in titanium alloy processing to solve some challenges, such as difficulty in chip breaking, large cutting forces, and high cutting temperatures. Based on the multi-region dynamic angles and the double-side wedge angle deformation mechanism, this study improves the vibration-assisted drilling (VAD) cutting forces and chip breaking model. The dynamic

The joining of sapphire with a Sn-3.5Ag-4Al solder was accomplished by a fast ultrasonic-assisted soldering (0.5 s) based on ultrasonic-assisted dipping in air at a low temperature of 250 °C. The sapphire joints were fabricated with different ultrasonic durations during the dipping. The uptrend of the shear strength of joints was composed of two processes: the formation of interfacial bonding and the

A new technique called micro-needle peening was proposed to improve the fatigue strength of arc-welded ultra-high strength steel joints. Use of a small tip pin (micro needle) makes it possible to introduce compressive residual stress and work hardening effects without causing the crack-like defect which is inevitable with conventional needle peening. The fatigue strength of micro-needle peened joints

The modified cold metal transfer (CMT) heat sources by adjusting the characteristic processing parameters were conducted in wire-arc additive manufacturing (WAAM) of AZ31 magnesium alloy for thin-wall component. The processing, microstructure, and mechanical behaviour were investigated. The CMT characteristic deposited a wide and shallow weld bead coupled with good wettability and low equivalent heat

The skin of an aircraft contains curved surface, which is a key component that determines its aerodynamic shape. During the manufacturing of its skin-parts, large springback often occurs, when conventional forming methods are used. Electromagnetic forming can reduce the springback substantially. In addition, the forming process enables moving coil discharge, which can be used to form large parts. In

An oscillating electromagnetic field weld pool support system combined with a welding sample travel mechanism was designed for improving the weld bead formation in full-penetration laser welding of A5083 aluminum alloy. The experimental results show that a proper oscillating electromagnetic field can effectively reduce the weld root sagging. When the root mean square of magnetic induction intensity

Due to harsh environment in the cutting area, access to the cutting region is still limited for the existing temperature sensors. As such, measuring temperature signals remains a challenge for real-time tool wear monitoring. In this paper, a polycrystalline cubic boron nitride (PCBN) cutting tool embedded with thin-film thermocouple (TFTC) was devised and used for tool wear monitoring during the cutting

Poor powder catchment efficiency, is a limiting factor in the adoption of Directed Energy Deposition for the processing of expensive materials, complex shapes and for the sake of energy efficiency. This study demonstrates a novel approach to improve powder catchment efficiency using a magnetic field to direct ferritic steel powder during deposition. Powder catchment efficiency increased to a value

With the aim of alleviating the residual thermal stress in the C/C-GH3044 joints, a novel composite brazing, which combines Ag-Ti reactive composite brazing and TiC particle-reinforced composite brazing, was adopted for joining C/C composite to Ni-based superalloy GH3044 using (Ag-10Ti)+TiC composite filler material. The results showed that the composite interlayer was strengthened by four kinds of

Selective laser sintering (SLS) and Multi Jet Fusion (MJF) are two of the most developed powder bed fusion additive manufacturing techniques for the manufacture of polymeric components. In this work, a systematic benchmark and comparison of polyamide 12 (PA12) parts printed by SLS and MJF was conducted on the physicochemical characterization of raw powder materials (EOS PA2200 and HP 3D HR PA12) and

Analytical formability models based upon in-plane proportional plane stress loading such as the Marciniak–Kuczynski (MK) model are commonly evaluated against forming limit curves (FLCs) obtained using Nakazima tests with out-of-plane deformation, non-linear strain paths and tool contact. The present study has conducted a comprehensive experimental characterization of a DP1180 advanced high strength

The manuscript presents some aspects of Professor Marciniak's life as well as a synthesis of his main contributions in metal forming.

How to coordinate the strength, ductility and electrical conductivity of Cu-Cr-Zr alloys has always been a difficult problem. Unlike most of previous reports on processing soft state (solution state) alloys, in the present study, a hard state (aged state) Cu-Cr-Zr alloy was subjected to one-step friction stir processing (FSP) at room temperature with more attentions paid to the evolution of grains

In this study, the contact interface friction, its reduction and the frictionless stress in ultrasonic vibration assisted forming process are investigated by a combination of experimental, analytical and numerical methods. Conventional and ultrasonic vibration assisted compression tests of pure titanium without lubrication are implemented. The flow stress is significantly lessened by applying the oscillation

Laser dressing technology is expected to solve the dressing problem of superabrasive forming grinding wheels. However, this technology is still in the initial stage of research, and is facing bottlenecks such as poor profiling accuracy due to the difficulty of tool setting of laser beam, uncontrolled sharpening topography due to laser focus characteristics, and reduced grain performance due to ablation

Mechanical performance of hot forming products is strongly related to microstructures and deformation behaviors during hot processing. Through dynamic recrystallization (DRX) kinetics analysis and simulation, evolution of microstructure and hot-compressive behavior of a solution-treated GH4169 superalloy at different deformation conditions were investigated. The DRX behavior confirmed by microstructure

Shear cutting is a prominent process in the chipless separation of metallic sheet materials. The cutting surface characteristics are the basis for quality assessment. Many present investigations deal with part quality and the influence of different process parameters, i.e., cutting edge geometry, punching speed and die clearance. Material failure occurs when the material's forming limit is reached

Fe/epoxy resin hybrid structures were fabricated via three-dimensional open-cellular porous Fe/TiB2 composite layers by an in-situ reaction synthesis process. Pores in the porous layer were filled with an epoxy resin to form an interpenetrating phase layer (IPL) consisting of epoxy resin and Fe/TiB2 composite. The relationship between the tensile joint strength perpendicular to the joint interface

The micro-texture fabricated on the substrate surface of coatings is an established method for enhancing the Physical Vapor Deposition (PVD) coatings adhesion. Currently, laser micromachining is widely used to prepare the micro-texture. Nevertheless, it suffers from the problem of low fabrication quality, such as irregular texture edges and irregular protrusions inside the textures. Meanwhile, to achieve

The non-uniform friction and lubrication are key factors that affect the slab quality during continuous casting. In order to present the complicated friction behavior of slab in the mold, a friction calculation model was built based on a full-scale heat transfer model. An inverse algorithm was applied to calculate the real heat flux by measuring temperatures from thermocouples buried in various locations

The gaseous atmosphere plays a major role in the quality of the manufactured parts in Laser Powder Bed Fusion (L-PBF) by protecting the metal from high temperature oxidation. If argon and nitrogen are the most commonly used gases, helium has almost never been considered as a possible candidate as a chemically inert shielding gas. To provide a better understanding of the influence of the gas atmosphere

In the present work, a novel Ni-Cu composite interlayer was prepared on the surface of A356 aluminum alloy solid insert using the chemical nickel-plating and electro-coppering technology, in order to restrain the generation of brittle phases and enhance the shear strength of A356 aluminum/AZ91D magnesium bimetal manufactured using a compound casting. The effect of the Ni-Cu composite interlayer on

Flange wrinkling is one of the most common defects affecting the forming quality of workpieces in conventional spinning. To this end, the flange wrinkling mechanism is analyzed and a new robust theoretical prediction model for the flange wrinkling is developed in this work. It is found that the initiation of flange wrinkling is closely related to the excessive circumferential compressive stress in

A previous study has found that applying ultrasonic vibration in laser joining of Polyethylene terephthalate (PET) plastic to Ti metal can greatly reduce bubbles formed in the joint. In this study, the theoretical basis on the combined effects of pressure and temperature fields on the trajectory of bubbles was analyzed using finite element simulation. A non-uniform temperature field influences the

Uniaxial compression is widely employed to investigate the constitutive behavior and microstructural developments of metallic materials at elevated temperatures. However, the heat exchange between work-piece and anvils leads to temperature gradient and inhomogeneous deformation within the work-piece, which weakens the reliability of the testing method. The problem is more serious for titanium alloys

In order to realize the CNC incremental forming of straight-wall part, a CNC incremental forming method for multi-directional adjustment of sheet postures based on the virtual auxiliary body was proposed. In the method, the sheet posture was adjusted based on the virtual auxiliary body which was set inside the straight-wall part to establish a gently inclined surface, thereby the forming angle was

Laser-additive welding using TiB2 powder with different weight fractions and sizes was applied to join a Ti-22Al-25Nb (at.%) alloy. In the heat-affected zone (HAZ), the O→B2 phase transformation led to the formation of a single B2 phase region. In the case of the joints produced using the TiB2 powder with a particle size of 4–10 μm, the fusion zone was composed of the B2 and intergranular TiB phases

Compensation of tool wear in micro-EDM milling of inclined surfaces is a difficult task due to variations of the radial engagement conditions of the tool with the workpiece. Traditional compensation methods based on off-line wear prediction are likely to be inaccurate, while methods involving tool measurements are time-consuming. In this research, the process dynamics when the tool is not fully engaged

AlN strengthening layers were prepared on the surface of the Al-Si alloy substrate by nitrogen arc discharge at various currents. The strengthening layer is mainly composed of AlN, Al and a small amount of Si. In the nitriding process, the melt from the melting region transports upward to form the layer and Si works as the catalyst. In this method, the nitriding reaction is rapid and stable, which

For understanding the processing-microstructure-properties correlation of high pressure die casting (HPDC) AZ91D alloy, 3D reconstruction was carried out to characterize the microstructural morphologies of castings produced by four designed HPDC processes. The influence of different parameters (vacuum, slow-shot speed, fast-shot speed) on porosity volume and morphology, defect band width and average

Friction stir welding (FSW) process is currently considered as a promising alternative to join aluminium alloys. Indeed, this solid-state welding technique is particularly recommended for the assembly of these materials. Since parts are not heated above their melting temperature, FSW process may prevent solidification defects encountered in joining aluminium alloys and known as limitations to the dissemination

During hot strip rolling, the lateral metal flow can change the longitudinal residual stress to reduce the risk of buckling deformation of the strip. The mechanism of lateral metal flow on residual stress was studied by combining a residual stress model with experimentation. A buckling risk coefficient was proposed to quantify the risk of buckling deformation. The calculated results show that the lateral

Pulse magneto-oscillation (PMO) treatment has attracted growing interest as a technique for grain refinement during solidification. Attempts to clarify the effects of PMO treatment parameters have not yet yielded definitive information, because inconsistent results have been reported for the effects of current intensity and pulses frequency on the resulting crystal structures. The present study has