scholarly journals Cold Isostatic Pressing to Improve the Mechanical Performance of Additively Manufactured Metallic Components

Materials ◽  
2019 ◽  
Vol 12 (15) ◽  
pp. 2495 ◽  
Author(s):  
Isidoro Iván Cuesta ◽  
Emilio Martínez-Pañeda ◽  
Andrés Díaz ◽  
Jesús Manuel Alegre
Keyword(s):  
Mechanical Response ◽  
Mechanical Performance ◽  
Hot Isostatic Pressing ◽  
Processing Technique ◽  
Cold Isostatic Pressing ◽  
Small Samples ◽  
Homogeneous Distribution ◽  
Post Processing ◽  
Isostatic Pressing ◽  
Punch Test

Additive manufacturing is becoming a technique with great prospects for the production of components with new designs or shapes that are difficult to obtain by conventional manufacturing methods. One of the most promising techniques for printing metallic components is binder jetting, due to its time efficiency and its ability to generate complex parts. In this process, a liquid binding agent is selectively deposited to adhere the powder particles of the printing material. Once the metallic piece is generated, it undergoes a subsequent process of curing and sintering to increase its density (hot isostatic pressing). In this work, we propose subjecting the manufactured component to an additional post-processing treatment involving the application of a high hydrostatic pressure (5000 bar) at room temperature. This post-processing technique, so-called cold isostatic pressing (CIP), is shown to increase the yield load and the maximum carrying capacity of an additively manufactured AISI 316L stainless steel. The mechanical properties, with and without CIP processing, are estimated by means of the small punch test, a suitable experimental technique to assess the mechanical response of small samples. In addition, we investigate the porosity and microstructure of the material according to the orientations of layer deposition during the manufacturing process. Our observations reveal a homogeneous distribution independent of these orientations, evidencing thus an isotropic behaviour of the material.

scholarly journals Evolution of the Microstructure and Mechanical Properties of a Ti35Nb2Sn Alloy Post-Processed by Hot Isostatic Pressing for Biomedical Applications

Metals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1027
Author(s):  
Joan Lario ◽  
Ángel Vicente ◽  
Vicente Amigó
Keyword(s):  
Powder Metallurgy ◽  
Mechanical Strength ◽  
Room Temperature ◽  
Hot Isostatic Pressing ◽  
Phase Changes ◽  
Post Processing ◽  
Isostatic Pressing ◽  
Porosity Reduction ◽  
Processing Step ◽  
Hip Process

The HIP post-processing step is required for developing next generation of advanced powder metallurgy titanium alloys for orthopedic and dental applications. The influence of the hot isostatic pressing (HIP) post-processing step on structural and phase changes, porosity healing, and mechanical strength in a powder metallurgy Ti35Nb2Sn alloy was studied. Powders were pressed at room temperature at 750 MPa, and then sintered at 1350 °C in a vacuum for 3 h. The standard HIP process at 1200 °C and 150 MPa for 3 h was performed to study its effect on a Ti35Nb2Sn powder metallurgy alloy. The influence of the HIP process and cold rate on the density, microstructure, quantity of interstitial elements, mechanical strength, and Young’s modulus was investigated. HIP post-processing for 2 h at 1200 °C and 150 MPa led to greater porosity reduction and a marked retention of the β phase at room temperature. The slow cooling rate during the HIP process affected phase stability, with a large amount of α”-phase precipitate, which decreased the titanium alloy’s yield strength.

Development Modes of Prior Free Sintering to Form a High-Density Fine Grain Ceramics after HIP

2014 ◽  
Vol 698 ◽  
pp. 457-460 ◽  
Author(s):  
Sergey Veselov ◽  
Natalya Belousova ◽  
Roman Timarevskiy ◽  
Nina Cherkasova
Keyword(s):  
Physical Properties ◽  
Structural Investigation ◽  
Hot Isostatic Pressing ◽  
Cold Isostatic Pressing ◽  
High Density ◽  
Isostatic Pressing ◽  
Fine Grain ◽  
Time Parameters ◽  
Temperature Time

In this paper the two methods of pre-operation green samples to hot isostatic pressing (HIP) were investigated. The influence the method of formation (uniaxial and cold isostatic pressing) and the temperature-time parameters on property of samples was analyzed. Structural investigation was carried out and physical properties of samples were defined. The recommendations for pre-operation and uses of sintering modes samples for HIP were given.

Microstructures and Properties of Cu–AISI304 Parts Fabricated by Improved Selective Laser Sintering

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Z. L. Lu ◽  
J. H. Liu ◽  
Y. S. Shi
Keyword(s):  
High Performance ◽  
Selective Laser Sintering ◽  
Hot Isostatic Pressing ◽  
Processing Parameters ◽  
Laser Sintering ◽  
Cold Isostatic Pressing ◽  
Isostatic Pressing ◽  
Cu Content ◽  
Mechanical Performances ◽  
Liquid Sintering

For fabricating complex AISI304 parts with high performance by advanced powder/metallurgy technologies, cold isostatic pressing (CIP) is introduced into selective laser sintering (SLS) combined with hot isostatic pressing (HIP), which is abbreviated to selective laser sintering/isostatic pressed (SLS/IP). The effect of processing parameters on the densification of Cu–AISI304 parts is analyzed and then the influence of Cu on their relative densities, metallurgical structures, and mechanical performances are investigated. The results show that relative densities of Cu–AISI304 parts fabricated by SLS/IP are mainly influenced by CIP pressure and sintering temperature, and it is interesting to find that the formula 1−D=(1−D0)e−kP is testified by the CIP of SLS/IP. There is an antidensification phenomenon resulting from Cu and AISI304 in liquid sintering, but the relative densities of Cu–AISI304 parts can be gradually improved in HIP with Cu content increasing from 1 wt % to 3 wt %. After the above-mentioned Cu–AIS304 parts are finally hot isostatic pressed, their metallurgical structures consist of sosoloid (Cu,Ni) and (Fe,Ni) besides austenite (Fe,Cr,Ni,C), their best mechanical performances are close to those of solution treated compact AISI304 when Cu content is 3 wt %.

Processing and Properties of Nanocrystalline Tetragonal Zirconia

2007 ◽  
Vol 336-338 ◽  
pp. 2300-2303 ◽  
Author(s):  
Martin Trunec ◽  
Karel Maca
Keyword(s):  
Fracture Toughness ◽  
Pore Size ◽  
Hot Isostatic Pressing ◽  
Tetragonal Zirconia ◽  
Cold Isostatic Pressing ◽  
Pressureless Sintering ◽  
Isostatic Pressing ◽  
Average Grain Size ◽  
Zirconia Nanopowders ◽  
Sintering Behaviour

Zirconia nanopowders (stabilized by 1.5 and 3 mol% Y2O3) with particle size below 10 nm were compacted by cold isostatic pressing. Pressureless sintering and hot isostatic pressing were applied to obtain dense nanocrystalline ceramics. The influence of the pore size in powder compacts on sintering behaviour was investigated. Green bodies pressed at 1000 MPa had a maximum pore size of 5 nm. These bodies were densified to a relative density of over 99.6% with an average grain size about 85 nm by pressureless sintering at 1100 °C. Indentation techniques were used to evaluate the hardness and fracture toughness of zirconia nanoceramics. The decrease in the yttria content from 3 to 1.5 mol% resulted in the toughness increasing from 5.3 to 11.1 MPa m1/2. The differences in fracture toughness of zirconia ceramics prepared with different yttria contents and by different sintering methods were discussed and their possible causes were proposed.

RESEARCH ON SHAPING TECHNOLOGY OF NANOCOMPOSITE WC-6Co POWDER AND PROPERTIES OF SINTERED COMPACTS

2006 ◽  
Vol 05 (02n03) ◽  
pp. 233-238 ◽  
Author(s):  
XIAOLIANG SHI ◽  
GANGQIN SHAO ◽  
XINGLONG DUAN ◽  
RUNZHANG YUAN
Keyword(s):  
Rupture Strength ◽  
Hot Isostatic Pressing ◽  
High Hardness ◽  
Cold Isostatic Pressing ◽  
Sintered Specimen ◽  
Volume Distribution ◽  
Vacuum Sintering ◽  
Transverse Rupture Strength ◽  
Isostatic Pressing ◽  
Die Pressing

The influences of powder extrusion molding (PEM), die pressing and cold isostatic pressing (CIP) on the green compacts and the sintered compacts of nanocrystalline WC-6 Co composite powder produced by spray pyrogenation-continuous reduction and carburization technology were researched. The results showed that the pore volume distribution, density and scanning electron microscopy (SEM) morphologies of fractured surface of powder extrusion molding or die pressing followed by the cold isostatic pressing consolidation green compacts were better than that of powder extrusion molding or die pressing. The green compacts were sintered by using vacuum sintering plus hot isostatic pressing (HIP), the sintered specimens were characterized by testing density, Rockwell A hardness, saturated magnetization, coercivity force, transverse rupture strength (TRS) and atomic force microscope (AFM) images, the results showed that sintered specimen of the green body that prepared by powder extrusion molding or die pressing followed by cold isostatic pressing had excellent properties of high strength and high hardness, transverse rupture strength of sintered specimen was more than 3100 MPa, Rockwell A hardness of sintered body was more than 93. Ultrafine WC-6 Co cemented carbide rods with excellent mechanical properties and fine microstructure were obtained.

scholarly journals Effects of Postprocess Hot Isostatic Pressing Treatments on the Mechanical Performance of EBM Fabricated TI-6Al-2Sn-4Zr-2Mo

Materials ◽  
2020 ◽  
Vol 13 (11) ◽  
pp. 2604 ◽  
Author(s):  
Miguel Lopez ◽  
Christina Pickett ◽  
Edel Arrieta ◽  
Lawrence E. Murr ◽  
Ryan B. Wicker ◽  
...  
Keyword(s):  
Grain Growth ◽  
Electron Emission ◽  
Mechanical Performance ◽  
Hot Isostatic Pressing ◽  
Alpha Phase ◽  
Grain Structure ◽  
Isostatic Pressing ◽  
Post Process ◽  
Equiaxed Grain ◽  
Thermionic Electron Emission

An essentially fully acicular alpha-prime martensite within an equiaxed grain structure was produced in an Electron Beam Melting (EBM)-fabricated Ti-6Al-2Sn-4Zr-2Mo (Ti6242) alloy using two different Arcam EBM machines: An A2X system employing tungsten filament thermionic electron emission, and a Q20 system employing LaB6 thermionic electron emission. Post-process Hot Isostatic Pressing (HIP) treatment for 2 h at 850, 950, and 1050 °C resulted in grain refinement and equiaxed grain growth along with alpha-prime martensite decomposition to form an intragranular mixture of acicular martensite and alpha at 850 °C, and acicular alpha phase at 950 and 150 °C, often exhibiting a Widmanstätten (basketweave) structure. The corresponding tensile yield stress and ultimate tensile strength (UTS) associated with the grain growth and acicular alpha evolution decreased from ~1 and ~1.1 GPa, respectively, for the as-fabricated Ti6242 alloy to ~0.8 and 0.9 GPa, respectively, for HIP at 1050 °C. The optimum elongation of ~15–16% occurred for HIP at 850 °C; for both EBM systems. Because of the interactive role played by equiaxed grain growth and the intragrain, acicular alpha microstructures, the hardness varied only by ~7% between 41 and 38 HRC.

Fundamental Properties of Monolithic Bentonite Buffer Material Formed by Cold Isostatic Pressing for High-Level Radioactive Waste Repository

1999 ◽  
Vol 556 ◽  
Author(s):  
S. Kawakami ◽  
Y Yamanaka ◽  
K. Kato ◽  
H. Asano ◽  
H. Ueda
Keyword(s):  
Hydraulic Conductivity ◽  
Radioactive Waste ◽  
Swelling Pressure ◽  
Cold Isostatic Pressing ◽  
Small Samples ◽  
Isostatic Pressing ◽  
High Level Radioactive Waste ◽  
Compacted Bentonite ◽  
Buffer Material ◽  
High Level

AbstractThe methods of fabrication, handling, and emplacement of engineered barriers used in a deep geological repository for high level radioactive waste should be planned as simply as possible from the engineering and economic viewpoints. Therefore, a new concept of a monolithic buffer material around a waste package have been proposed instead of the conventional concept with the use of small blocks, which would decrease the cost for buffer material. The monolithic buffer material is composed of two parts of highly compacted bentonite, a cup type body and a cover. As the forming method of the monolithic buffer material, compaction by the cold isostatic pressing process (CIP) has been employed.In this study, monolithic bentonite bodies with the diameter of about 333 mm and the height of about 455 mm (corresponding to the approx. 1/5 scale for the Japanese reference concept) were made by the CIP of bentonite powder. The dry densities: pd of the bodies as a whole were measured and the small samples were cut from several locations to investigate the density distribution. The swelling pressure and hydraulic conductivity as function of the monolithic body density for CIP-formed specimens were also measured.High density ( ρd: 1.4–2.0 Mg/m3) and homogeneous monolithic bodies were formed by the CIP. The measured results of the swelling pressure (3–15 MPa) and hydraulic conductivity (0.5–1.4×10−3 m/s) of the specimens were almost the same as those for the uniaxial compacted bentonite in the literature. It is shown that the vacuum hoist system is an applicable the handling method for emplacement of the monolithic bentonite.

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