Fused Filament Fabrication for Metallic Materials: A Brief Review.

Fused filament fabrication (FFF) is an extrusion-based additive manufacturing (AM) technology mostly used to produce thermoplastic parts. However, producing metallic or ceramic parts by FFF is also a sintered-based AM process. FFF for metallic parts can be divided into five steps: (1) raw material selection and feedstock mixture (including palletization), (2) filament production (extrusion), (3) production of AM components using the filament extrusion process, (4) debinding, and (5) sintering.

Adding Value to Secondary Aluminum Casting Alloys: A Review on Trends and Achievements.

Aluminum is a critical element of the circular economy as it can be recycled several times. Moreover, Al recycling is a more economically and environmentally efficient procedure than the primary Al production from ores. Secondary aluminum alloys are mostly used in casting applications since it is possible to accommodate their chemical composition through secondary manufacturing processes.

The Effect of Ultrasonic Agitation on the Seedless Growth of Cu on Ru-W Thin Films.

Ru attracted considerable attention as a candidate to replace TaN as a diffusion barrier layer for Cu interconnect metallisation. The addition of W improves the diffusion barrier properties of Ru but appears to weaken the adhesion strength between the barrier and Cu and the direct (seedless) electroplatability behaviour. Although Cu can be directly electroplated on near equimolar Ru-W thin films, no complete substrate coverage is obtained.

A Study on a Cast Steel Reinforced with WC-Metal Matrix Composite.

This study seeks to investigate the local reinforcement of low carbon cast steel specimens with WC-metal matrix composites (WC-MMCs), to obtain a new material effective in competing with hard alloy steels. For this purpose, a powder compact of tungsten carbide (WC) and iron (Fe) was prepared and placed in the mold cavity before casting. The reactions that occurred with the molten steel led to the formation of the WC-MMC and, consequently, to the local reinforcement of the steel.

Co-W Barrier Layers for Metallization of Copper Interconnects: Thermal Performance Analysis.

The back-end-of-line (BEOL) copper interconnect structure has been subjected to downscaling for the last two decades, while the materials used for conforming and assuring its physical integrity during processing have faced significant obstacles as the single-digit nanometer process node is implemented. In particular, the diffusion barrier layer system comprised of Ta/TaN has faced major constraints when it comes to the electrical performance of the smaller Cu lines, and thus alternative formulations have been investigated in recent years, such as Ru-Ta or Co-W alloys. In this work, we assess how PVD (physical vapor deposition) deposited equimolar Co-W films perform when exposed to different vacuum annealing temperatures and how these films compare with the Ta adhesion layer used for Cu seeding in terms of dewetting resistance.

Seedless Cu Electroplating on Ru-W Thin Films for Metallisation of Advanced Interconnects.

For decades, Ta/TaN has been the industry standard for a diffusion barrier against Cu in interconnect metallisation. The continuous miniaturisation of transistors and interconnects into the nanoscale are pushing conventional materials to their physical limits and creating the need to replace them. Binary metallic systems, such as Ru-W, have attracted considerable attention as possible replacements due to a combination of electrical and diffusion barrier properties and the capability of direct Cu electroplating.

Production and Characterization of Austenitic Stainless Steel Cast Parts Reinforced with WC Particles Fabricated by Ex Situ Technique.

In this work, austenitic stainless steel specimens were locally reinforced with WC particles. The reinforcements were fabricated via an ex situ technique based on powder technology. Mixtures of WC, Fe, and M0101 binder were cold-pressed to obtain powder compacts.

Inconel 625/AISI 413 Stainless Steel Functionally Graded Material Produced by Direct Laser Deposition.

Functionally graded material (FGM) based on Inconel 625 and AISI 431 stainless steel powders was produced by applying the direct laser deposition (DLD) process. The FGM starts with layers of Inconel 625 and ends with layers of 431 stainless steel having three intermediate zones with the composition (100-X)% Inconel 625-X% 431 stainless steel, X = 25, 50, and 75, in that order. This FGM was deposited on a 42CrMo4 steel substrate, with and without preheating.

Production of TiC-MMCs Reinforcements in Cast Ferrous Alloys Using In Situ Methods.

This literature review aims to summarize the research conducted on the production of locally reinforced ferrous castings based on metal matrix composites reinforced with TiC (TiC-MMCs). One way to improve the wear resistance of cast components is to reinforce critical regions locally with metal matrix composites (MMCs) without changing the toughness of the component core. The in situ method of self-propagating high-temperature synthesis is one of the main approaches for the production of this enhanced material.

Seedless Cu Electroplating on Co-W Thin Films in Low pH Electrolyte: Early Stages of Formation.

The use of Ta/TaN barrier bilayer systems in electronic applications has been ubiquitous over the last decade. Alternative materials such as Co-W or Ru-W alloys have gathered interest as possible replacements due to their conjugation of favourable electrical properties and barrier layer efficiency at reduced thicknesses while enabling seedless Cu electroplating. The microstructure, morphology, and electrical properties of Cu films directly electrodeposited onto Co-W or Ru-W are important to assess, concomitant with their ability to withstand the electroplating baths/conditions.

Preparation and Microstructural Characterization of a High-Cr White Cast Iron Reinforced with WC Particles.

High-chromium white cast iron (WCI) specimens locally reinforced with WC-metal matrix composites were produced via an ex situ technique: powder mixtures of WC and Fe cold-pressed in a pre-form were inserted in the mold cavity before pouring the base metal. The microstructure of the resulting reinforcement is a matrix of martensite (α') and austenite (γ) with WC particles evenly distributed and (Fe,W,Cr)C carbides that are formed from the reaction between the molten metal and the inserted pre-form. The (Fe,W,Cr)C precipitation leads to the hypoeutectic solidification of the matrix and the final microstructure consists of martensite, formed from primary austenite during cooling and eutectic constituent with (Fe,Cr)C and (Fe,W,Cr)C carbides.

Microstructural Characterization of TiC-White Cast-Iron Composites Fabricated by In Situ Technique.

High-chromium white cast-iron specimens locally reinforced with TiC-metal matrix composites were successfully produced via an in situ technique based on combustion synthesis. Powder mixtures of Ti, Al, and graphite were prepared and compressed to fabricate green powder compacts that were inserted into the mold cavity before the casting. The heat of the molten iron causes the ignition of the combustion reaction of the reactant powders, resulting in the formation of the TiC by self-propagating high-temperature synthesis.

EBSD Analysis of Metal Matrix Nanocomposite Microstructure Produced by Powder Metallurgy.

The development of metal nanocomposites reinforced by carbon nanotubes (CNTs) remains a focus of the scientific community due to the growing need to produce lightweight advanced materials with unique mechanical properties. However, for the successful production of these nanocomposites, there is a need to consolidate knowledge about how reinforcement influences the matrix microstructure and which are the strengthening mechanisms promoting the best properties. In this context, this investigation focuses on the study of the reinforcement effect on the microstructure of an Ni-CNT nanocomposites produced by powder metallurgy.

Microstructural Characterization of Carbon Nanotubes (CNTs)-Reinforced Nickel Matrix Nanocomposites.

This research focuses on the microstructural characterization of nickel matrix composites reinforced by carbon nanotubes (CNTs). The nanocomposites were produced by a conventional powder metallurgy process and the dispersion of CNTs and mixture with nickel powders was performed in a single step by ultrasonication. Microstructural characterization of Ni-CNT nanocomposites was performed by scanning and transmission electron microscopy, electron backscattered diffraction, high-resolution transmission electron microscopy, selected area electron diffraction, and fast Fourier transform analyses.

Microstructural Characterization of Aluminum-Carbon Nanotube Nanocomposites Produced Using Different Dispersion Methods.

This research focuses on characterization of the impact of dispersion methods on aluminum-carbon nanotubes (Al-CNTs) nanocomposite structure. Nanocomposites were produced by a conventional powder metallurgy process after the dispersion of the CNTs on the Al powders, using two approaches: (1) the dispersion of CNTs and mixture with Al powders were performed in a single step by ultrasonication; and (2) the CNTs were previously untangled by ultrasonication and then mixed with Al powders by ball milling. Microstructural characterization of Al-CNT nanocomposites was performed by optical microscopy, scanning and transmission electron microscopy, electron backscatter diffraction, and high-resolution transmission electron microscopy (HRTEM).

TEM and HRTEM characterization of TiAl diffusion bonds using Ni/Al nanolayers.

Diffusion bonding of TiAl alloys can be enhanced by the use of reactive nanolayer thin films as interlayers. Using these interlayers, it is possible to reduce the conventional bonding conditions (temperature, time, and pressure) and obtain sound and reliable joints. The microstructural characterization of the diffusion bond interfaces is a fundamental step toward understanding and identifying the bonding mechanisms and relating them to the strength of the joints.

Study of ink paper sensor based on aluminum/carbon nanotubes agglomerated nanocomposites.

Agglomerated nanocomposites based on Aluminum/Carbon Nanotubes (AI/CNT) were produced by an arc discharge technique under argon/acetone atmosphere and ultrasonically dispersed in distilled water to form an ink-like composite. This ink was spread onto commercial paper to produce a conductive thick film. Experimental results show that the electrical resistance of Al/CNT nanocomposite on paper changes when a mechanical stress and/or heat is applied.