Hot Isostatic Pressing Method Research Articles

Investigation of the effect of HIP processing on the physical and mechanical characteristics of parts obtained by the SLM method

In this paper presents the results of studying the powder material AISI 321. Selective laser melting (SLM) of the samples was carried out in modes with a change in the radiation power. The subsequent processing of the samples by the method of hot isostatic pressing (HIP) was carried out. The roughness of the surfaces and the microhardness of the samples before and after the HIP were studied.

Study of beryllium hardening obtained by powder metallurgy

In the first part of the article the results of the study of powder hardening processes occurring during beryl powders consolidation by the hot pressing method are shown. The dependences of the content and morphology of the hardening phase depending on the content of low-melting impurities on the sintered Beryllium powder grains surface have been studied. A hypothesis is proposed that explains the transition of an oxide film from an amorphous to a crystalline state – devitrification, and the effect of low-melting impurities on the mechanism of the devitrification process and, as a consequence, on the effect of "dispersion-grain boundary" hardening. This hypothesis is based on theoretical confirmation with the provision of graphic material demonstrating the process of devitrification, accompanied by a dispersed-grain-boundary hardening mechanism. The final results of statistical processing carried out on industrial batches showing the dependence of the impurities content influence on the properties of hot-pressed beryllium are presented. In the second part of the article the results of studying the effect of hardening of beryllium obtained in the process of sintering by the method of hot isostatic pressing (HIP) are shown depending on the temperature of powders consolidation. Based on the results of electron microscopic studies, the dynamics of the reinforcing phase formation at the grain boundaries of sintered beryllium is shown. The quantitative dependence of the precision elastic limit and the conditional yield stress of gas-statically compressed beryllium on the size of the strengthening beryllium oxide particles and the consolidation temperature of the powders have been established. The resulting equation gives a description of the "dispersed-grain-boundary" hardening mechanism of isostatically pressed beryllium. All dependencies are also represented by graphic material reflecting the essence of the research.

Study on Hardening Potential of Isostatic Pressed Beryllium

The effect of beryllium hardening has been studied. Beryllium is sintered by method of hot isostatic pressing (HIP), depending on the temperature of powders pressing. The research results of electron microscopic studies were the base for demonstrating formation of the hydraulic phase at the grain boundary of sintered beryllium and influence of the reinforcing phase on the mechanical properties of the HIP blank. The dependence of beryllium precision elastic limit and conventional yield strength from the size of the reinforcing particles of beryllium oxide has been found. The obtained equation provides a description of the “dispersion-grain-boundary" mechanism of isostatic pressed Beryllium hardening.

Consolidation and Simulations of Hot Isostatic Pressing of Selective Laser Sintered Stainless Steel Parts

The method of hot isostatic pressing of selective laser sintered parts is proposed to make metal parts with complex structure and high density. The forming process is greatly simplified by removing the operation of cold isostatic pressing. Therefore, it is a new effective method for manufacturing complex metal parts. A bevel gear has been made by this method using AISI304 stainless steel. The simulation of hot isostatic pressing has been carried out using the Drucker–Prager–Cap model in ABAQUS/Standard and the hyperbolic-sine creep subroutine. The simulation results have been compared with those of the experiments. The final relative density of the parts by this method increases up to 0.90 from original 0.37. The results show that there is only big volumetric contraction without obvious distortions. The errors of the main dimensions are within 6%, which indicates good agreement between the experimental results and the calculated results.

Demonstration of Excellent J c Performance in (AE,Na)Fe2As2 (AE: Sr, Ba) PIT Wires

Na-substituted 122-type iron-based superconductors were synthesized and fabricated into superconducting tapes and wires. Good Jc performance of Ag-sheathed Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.45</sub> Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.55</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> pressed tapes was demonstrated, and it was further improved by using AgSn as a sheath material. The improved J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> characteristics are due to the reduction of the optimum sintering temperature by ~100 °C, which suppressed the reaction between the sheath and the core. However, the fabrication of good Sr <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.45</sub> Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.55</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> round wire using the hot isostatic press method failed, due possibly to the segregation of Na in the core. To avoid the segregation of Na, we fabricated round wires employing (Ba,Na)Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> rather than underdoped (Sr,Na)Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> . J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> in Ba <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.6</sub> Na <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0.4</sub> Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> round wire processed 700 °C under the pressure of 175 MPa reached 1.5 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> and 2.0 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sup> A/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> at self-field and 100 kOe, respectively. These values are more than fifty percent of the largest J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> in (Ba,K)Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> round wires, demonstrating the excellent performance of (Ba,Na)Fe <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> As <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> wires.

Change in the Microstructure of Ni Alloy Disk Workpieces for Gas Turbine Engines Produced by the HIP + Deformation Method

Abstract—The changes in the microstructure during thermomechanical treatment under different regimes of a new granulated heat-resistant alloy based on VZh178P nickel obtained by the method of hot isostatic pressing and subsequent hot deformation (HIP + deformation) are studied. The change in the grain size of the γ matrix after the main operations of the technological conversion is shown; the dynamics of their growth in hardening below and above the temperature of total dissolution of the γ' phase and the microstructure after the total thermal treatment are shown.

The effect of sintering temperature on microstructure and mechanical properties of alloys produced by using hot isostatic pressing method

In this study, a new matrix material was produced via HIP (Hot Isostatic Pressing) method by adding Cobalt and Nikel elements to CuSn (85/15) bronze alloy at certain ratios and the effect of sintering temperature during the production was examined. One of the biggest advantages of the HIP method is that the heat and pressure are applied at the same time during sintering process. Thus, all or almost all of the gaps during the production were removed and a more dense material was obtained. During the operation, it was kept constant that the sintering pressure was 30 MPa and the sintering time was 15 min, and the sintering temperature was selected as the variable parameter between 700 °C and 800 °C. The sintering process was carried out under the vacuum condition after the moment of first combustion. The produced samples were then metallographically prepared and SEM and EDS analyses were carried out for microstructure studies. Microhardness was taken from the samples and three-point bending test was carried out in order to examine the mechanical behaviors of the samples. Finally the density test was applied to the samples and their experimental and theoretical densities were calculated. As a result, it was observed that more homogeneous samples were obtained by increasing the sintering temperature.

Behavior of tungsten fiber-reinforced tungsten based on single fiber push-out study

To overcome the intrinsic brittleness of tungsten (W), a tungsten fiber-reinforced tungsten-composite material (Wf/W) is under development. The composite addresses the brittleness of W by extrinsic toughening through the introduction of energy dissipation mechanisms. These mechanisms allow the reduction of stress peaks and thus improve the materials resistance against crack growth. They do not rely on the intrinsinc material properties such as ductility. By utilizing powder metallurgy (PM) one could benefit from available industrialized approaches for composite production and alloying routes. In this contribution the PM method of hot isostatic pressing (HIP) is used to produce Wf/W samples containing W fibers coated with an Er2O3 interface. Analysis of the matrix material demonstrates a dense tungsten bulk, a deformed fiber and a deformed, but still intact interface layer. Metallographic analysis reveals indentations of powder particles in the interface, forming a complex 3D structure. Special emphasis is placed on push-out tests of single fiber HIP samples, where a load is applied via a small indenter on the fiber, to test the debonding and frictional properties of the Er2O3 interface region enabling the energy dissipation mechanisms. Together with the obtained experimental results, an axisymmetric finite element model is discussed and compared to existing work. In the HIP Wf/W composites the matrix adhesion is rather large and can dominate the push-out behavior. This is in contrast to the previously tested CVD produced samples.

Powder Metallurgical Tungsten Fiber-Reinforced Tungsten

The composite material tungsten fiber-reinforced tungsten (Wf/W) addresses the brittleness of tungsten by extrinsic toughening through introduction of energy dissipation mechanisms. These mechanisms allow the release of stress peaks and thus improve the materials resistance against crack growth. Wf/W samples produced via chemical vapor infiltration (CVI) indeed show higher toughness in mechanical tests than pure tungsten. By utilizing powder metallurgy (PM) one could benefit from available industrialized approaches for composite production and alloying routes. In this contribution the PM method of hot isostatic pressing (HIP) is used to produce Wf/W samples. A variety of measurements were conducted to verify the operation of the expected toughening mechanisms in HIP Wf/W composites. The interface debonding behavior was investigated in push-out tests. In addition, the mechanical properties of the matrix were investigated, in order to deepen the understanding of the complex interaction between the sample preparation and the resulting mechanical properties of the composite material. First HIP Wf/W single-fiber samples feature a compact matrix with densities of more than 99% of the theoretical density of tungsten. Scanning electron microscopy (SEM) analysis further demonstrates an intact interface with indentations of powder particles at the interface-matrix boundary. First push-out tests indicate that the interface was damaged by HIPing.

Microchemical characterisation of carbon–metal interface in Ti6Al4VSiCf composites

AbstractThe composite of Ti6Al4V alloy, reinforced by unidirectional SiC fibres coated with graphite, has been investigated through a new fabrication process, roll diffusion bonding (RDB), developed at the CSM laboratories. Microchemical characteristics of the interface between carbon (coating of SiC fibres) and metal (Ti6Al4V) have been investigated by means of XPS, multipoint AES and photoemission spectromicroscopy (Electron Spectroscopy for Chemical Analysis (ESCA) microscopy beamline at the ELETTRA synchrotron light source). The results obtained revealed that the composition of the fibre–metal interface is similar to that of the composites produced by conventional method of hot isostatic pressing (HIP).In the matrix, near to the fibres, the anomalous shape of Al 2p signal indicated the presence of CAl atom pairs which are responsible for the anelastic characteristics of the composite. Copyright © 2010 John Wiley &amp; Sons, Ltd.

The effect of copper-steel joining technology on the radiation resistance of copper alloys

Abstract Currently, when developing the components and units of the ITER first wall and divertor different technologies are considered for the production of Cu/SS-type joints: explosion welding, high-temperature brazing, etc. But, the most promising for the production of joints seems to be the method of hot isostatic pressing (HIP). A high HIP temperature of ∼950°C causes considerable changes in the properties of copper alloys (for steel the HIP effect is less substantial). This paper presents the first results of the investigation into the radiation resistance of DS copper alloys (GlidCop A1251G and MAGT 0.2) and PH copper alloy (Cu-Cr-Zr), irradiated to 0.2 dpa at Tirr= 150°C and 300°C. The alloys were investigated both in the optimized state and after the HIP procedure. The investigations demonstrated that after the HIP procedure GlidCopA125IG-type alloy, when irradiated, had a satisfactory level of strength and plasticity properties at Ttest= T irr =150°C and embrittled strongly at T test=T irr=300°C....

Tl2Ba2Ca2Cu3O10 Bulk Samples Prepared by Hot Isostatic Press Method

The hot isostatic press method was used to prepare Tl2Ba2Ca2Cu3O10 bulk samples. Samples with a high mass density were obtained. It was shown that in such prepared samples most superconducting grains are compressed closely together, thus improving the weak links between grains and resulting in a higher transport critical current density.

High-strength ceramics from Zr02

Specimens of powder fabricated by codeposition of zirconium and yttrium nitrates with the using special dry ing techniques and regranulation by the method of hot isostatic pressing have been tested in air allowing for the laws of compaction of granulated powder at a final firing temperature of about 1500°C. The resulting ma terial had the following properties: a density p = 5.91 g/cm (98% of the theoretical value), an ultimate bend ing strength a = 1100 MPa, and a crack resistance K = 19.5 MPa . rn A set of the specimens was sub jected to hot isostatic pressing after natural sintering and exhibited the following properties: p = 6.08 g/cm = 1400 MPa, K = 17.5 MPa · m1/2.

拡散接合（ＨＩＰ）法により製作した放射光Ｘ線ベリリウム窓用フランジの評価

拡散接合（ＨＩＰ）法により製作した放射光Ｘ線ベリリウム窓用フランジの評価