scholarly journals Micro Feature Enhanced Sinter Bonding of Metal Injection Molded (MIM) Parts to Solid Substrate

2011 ◽  
Author(s):  
Thomas Martens ◽  
Laine Mears
Keyword(s):  
Plastic Deformation ◽  
Solid Substrate ◽  
Full Density ◽  
Metal Powders ◽  
Solid Substrates ◽  
Injection Molded ◽  
Bond Strengths ◽  
Sinter Bonding ◽  
Micro Features ◽  
Plastic Injection

In MIM, fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density. The obstacle to sinter bonding a MIM part to a conventional (solid) substrate lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. A structure of micro features molded onto the surface of the MIM part allows for shrinkage while bonding to the substrate. The micro features tolerate certain plastic deformation to permit the shrinkage without causing cracks after the initial bonds are established. In a first series of tests, bond strengths of up to 80% of that of resistance welds have been achieved. This paper describes how the authors developed their proposed method of sinter bonding and how they accomplished effective sinter bonds between MIM parts and solid substrates.

Direct Sinter Bonding of Metal Injection-Molded Parts to Solid Substrate Through Use of Deformable Surface Microfeatures

2013 ◽  
Vol 1 (1) ◽  
Author(s):  
Thomas Martens ◽  
M. Laine Mears
Keyword(s):  
Injection Molding ◽  
Solid Substrate ◽  
Metal Injection Molding ◽  
Full Density ◽  
Metal Powders ◽  
Molded Parts ◽  
Primary Obstacle ◽  
Injection Molded ◽  
Sinter Bonding ◽  
Micro Features

In the metal injection molding (MIM) process, fine metal powders are mixed with a binder and injected into molds, similar to plastic injection molding. After molding, the binder is removed from the part, and the compact is sintered to almost full density. Though able to create high-density parts of excellent dimensional control and surface finish, the MIM process is restricted in the size of part that can be produced, due to gravitational deformation during high-temperature sintering and maximum thickness requirements to remove the binding agents in the green state. Larger parts could be made by bonding the green parts to a substrate during sintering; however, a primary obstacle to this approach lies in the sinter shrinkage of the MIM part, which can be up to 20%, meaning that the MIM part shrinks during sintering, while the conventional substrate maintains its dimensions. This behavior would typically inhibit bonding and/or cause cracking and deformation of the MIM part. In this work, we present a structure of micro features molded onto the surface of the MIM part, which bonds, deforms, and allows for shrinkage while bonding to the substrate. The micro features tolerate plastic deformation to permit the shrinkage without causing cracks after the initial bonds are established. In a first series of tests, bond strengths of up to 80% of that of resistance welds have been achieved. This paper describes how the authors developed their proposed method of sinter bonding and how they accomplished effective sinter bonds between MIM parts and solid substrates.

scholarly journals Copper-Tantalum Metal Matrix Composites Consolidated from Powder Blends by Severe Plastic Deformation

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1010
Author(s):  
Zachary S. Levin ◽  
Michael J. Demkowicz ◽  
Karl T. Hartwig
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Metal Matrix Composites ◽  
Metal Matrix ◽  
Equal Channel Angular Extrusion ◽  
Rate Sensitivity ◽  
Matrix Composites ◽  
Metal Powders ◽  
Tantalum Metal ◽  
Mechanical Bonding

We investigated the effectiveness of severe plastic deformation by equal channel angular extrusion (ECAE) for consolidation of metal powders into metal matrix composites. Equal volumes of copper (Cu) and tantalum (Ta) powders were consolidated at ambient temperature via different ECAE routes. Composites processed by ECAE routes 4E and 4Bc were also processed at 300 °C. The resulting materials were characterized by scanning electron microscopy (SEM) and compression testing. Processing by route 4Bc at 300 °C resulted in the highest compressive strength, lowest anisotropy, and least strain rate sensitivity. We conclude that the superior properties achieved by this route arise from mechanical bonding due to interlocking Cu and Ta phases as well as enhanced metallurgical bonds from contact of pristine metal surfaces when the material is sheared along orthogonal planes.

scholarly journals Optical nanomanipulation on solid substrates via optothermally-gated photon nudging

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jingang Li ◽  
Yaoran Liu ◽  
Linhan Lin ◽  
Mingsong Wang ◽  
Taizhi Jiang ◽  
...  
Keyword(s):  
Colloidal Particles ◽  
Solid Substrate ◽  
Optical Scattering ◽  
Functional Nanostructures ◽  
Non Invasive ◽  
Solid Substrates ◽  
All Optical ◽  
Scattering Force ◽  
Reconfigurable Assembly

AbstractConstructing colloidal particles into functional nanostructures, materials, and devices is a promising yet challenging direction. Many optical techniques have been developed to trap, manipulate, assemble, and print colloidal particles from aqueous solutions into desired configurations on solid substrates. However, these techniques operated in liquid environments generally suffer from pattern collapses, Brownian motion, and challenges that come with reconfigurable assembly. Here, we develop an all-optical technique, termed optothermally-gated photon nudging (OPN), for the versatile manipulation and dynamic patterning of a variety of colloidal particles on a solid substrate at nanoscale accuracy. OPN takes advantage of a thin surfactant layer to optothermally modulate the particle-substrate interaction, which enables the manipulation of colloidal particles on solid substrates with optical scattering force. Along with in situ optical spectroscopy, our non-invasive and contactless nanomanipulation technique will find various applications in nanofabrication, nanophotonics, nanoelectronics, and colloidal sciences.

scholarly journals Top-Down Reactive Approach for the Synthesis of Disordered ZrN Nanocrystalline Bulk Material from Solid Waste

Nanomaterials ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 1826
Author(s):  
Mohamed Sherif El-Eskandarany ◽  
Sultan Majed Al-Salem ◽  
Naser Ali
Keyword(s):  
Solid Waste ◽  
Bulk Material ◽  
Chemical Properties ◽  
Morphological Characteristics ◽  
Zirconium Nitride ◽  
Full Density ◽  
Face Centered Cubic ◽  
Transition Metal Nitrides ◽  
Metal Powders ◽  
Fcc Phase

Transition metal nitrides possess superior mechanical, physical, and chemical properties that make them desirable materials for a broad range of applications. A prime example is zirconium nitride (ZrN), which can be obtained through different fabrication methods that require the applications of high temperature and pressure. The present work reports an interesting procedure for synthesizing disordered face centered cubic (fcc)-ZrN nanoparticles through the reactive ball milling (RBM) technique. One attractive point of this study is utilizing inexpensive solid-waste (SW) zirconium (Zr) rods as feedstock materials to fabricate ZrN nanopowders. The as-received SW Zr rods were chemically cleaned and activated, arc-melted, and then disintegrated into powders to obtain the starting Zr metal powders. The powders were charged and sealed under nitrogen gas using a pressurized milling steel vial. After 86 ks of milling, a single fcc-ZrN phase was obtained. This phase transformed into a metastable fcc-phase upon RBM for 259 ks. The disordered ZrN powders revealed good morphological characteristics of spherical shapes and ultrafine nanosize (3.5 nm). The synthetic ZrN nanopowders were consolidated through a spark plasma sintering (SPS) technique into nearly full-density (99.3% of the theoretical density for ZrN) pellets. SPS has proven to be an integral step in leading to desirable and controlled grain growth. Moreover, the sintered materials were not transformed into any other phase(s) upon consolidation at 1673 K. The results indicated that increasing the RBM time led to a significant decrease in the grain size of the ZrN powders. As a result, the microhardness of the consolidated samples was consequently improved with increasing RBM time.

scholarly journals UV/Ozone Surface Treatment for Bonding of Elastomeric COC-Based Microfluidic Devices

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 943
Author(s):  
Eva Gleichweit ◽  
Christian Baumgartner ◽  
Reinhard Diethardt ◽  
Alexander Murer ◽  
Werner Sallegger ◽  
...  
Keyword(s):  
Microfluidic Devices ◽  
Thermoplastic Elastomer ◽  
Bonding Process ◽  
Test Method ◽  
Polymer Materials ◽  
Surface Activation ◽  
Molded Parts ◽  
Injection Molded ◽  
Bond Strengths ◽  
Uv Ozone

Reliable bonding of microstructured polymer parts is one of the major challenges in industrial fabrication of microfluidic devices. In the present work, the effects of a UV/ozone surface activation on the bonding process were investigated for the combination of a commonly used thermoplastic cyclic olefin copolymer (COC) with an elastomeric COC (eCOC) as a new thermoplastic elastomer material. Bonding was studied using two-component injection molded parts of COC and eCOC, together with microfluidic COC chips. Surface activation and bonding process parameters were optimized and bond strengths were characterized by the wedge test method. The results showed that strong bonding of this polymer materials combination can be achieved at temperatures significantly below the bulk glass transition temperature of COC.

Powder characterization and part density for powder bed fusion of 17-4 PH stainless steel

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Sean Daniel Dobson ◽  
Thomas Louis Starr
Keyword(s):  
Particle Size ◽  
Stainless Steel ◽  
Flow Behavior ◽  
Full Density ◽  
Powder Bed Fusion ◽  
Metal Powders ◽  
Production Environment ◽  
Content Type ◽  
Powder Bed ◽  
Part Density

Purpose Characteristics of the metal powder are a key factor in the success of powder bed fusion (PBF) additive manufacturing. Powders for PBF from different manufacturers may have a different particle size and/or bulk packing and flow behavior. Powder properties change as the powder is reused for multiple builds. This study seeks to measure the variability of commercial 17-4 PH stainless steel powders to determine the effect of powder variability on part density and demonstrate characterization methods that ensure part quality. Design/methodology/approach Commercial atomized metal powders from four different vendors were produced with two different atomizing gases (N2 and argon). Powder was characterized in both new and extensively reused conditions. All powders were characterized for flow and packing behavior, particle size and internal porosity. Coupons were manufactured using the laser PBF process with optimized scan strategy and exposure parameters. The quality of fabricated parts was measured using bulk density measurement. Findings Despite differences in powder flowability and particle size, fully dense parts (>99 per cent) were produced using all powders, except one. Residual porosity in these parts appeared to result from gas trapped in the powder particles. The powder with extensive reuse (400+ h in machine fabrication environment) exhibited reduced flowability and increased fraction of fine particles, but still produced full density parts. Originality/value This study demonstrates that full density parts can be fabricated using powders with a range of flowability and packing behavior. This suggests that a single flowability measurement may be sufficient for quality assurance in a production environment.

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