Powder Hot Isostatic Pressing Research Articles

High density processing of high performance ferrous materials : H.G. Rutz, F.G. Hanejko. (Hoeganaes Corporation, Riverton, New Jersey, USA), Int. J. Powder Metallurgy, vol 31, no 1, 1995, 9–17

Porous biomedical implants are known for their improved osseointegration due to the ingrowth of bone tissues, combined with a lower elastic modulus to solid implants, resulting in a reduced likelihood for stress shielding and implant loosening. In this work, the control of the porosity content in capsule-free powder hot isostatic pressing (CF-HIPing) of 316L stainless steel was investigated. The proposed approach utilises cold isostatic pressing (CIPing) to form green compacts using rubber moulds, followed by CF-HIPing under suitable conditions. Porosity control was attained via the selection of the powder particle size used in creating the green compacts. The microstructural and mechanical properties development of the CF-HIPed structures was studied using optical and scanning electron microscopy, micro-computer tomography, hardness, and compression testing. The occurrence of powder necking was visualised using electron backscattered diffraction. The results showed a significant increase in the pore fraction of the samples by increasing the particle size of the powder. However, increasing the particle size was also associated with a drop in the elastic modulus, compressive strength, ductility, and hardness of the final structures. Nonetheless, porous structures with elastic modulus between 17 and 30 GPa were successfully produced using a powder particle size range of 32–50 μm, matching the elastic modulus of human bones.

Some properties of semiconducting IrSb3

Polycrystalline p-type samples of IrSb3 and Ir0.5Rh0.5Sb3 have been made by hot isostatic pressing of powders. A number of properties such as thermal expansion coefficient, sound velocity, thermal conductivity, electrical conductivity, Seebeck coefficient, and carrier concentration have been measured. These compounds show promise as thermoelectric materials.

Finite element simulation of hot isostatic pressing of metal powders

A finite element simulation of hot isostatic pressing of metal powders is studied using a mixed formulation method having velocity and pressure as nodal variables. A review of various methodologies formulated for the finite element modeling of hot isostatic pressing of powders is also presented. The constitutive relations considered are based on the theory of plasticity for powder material under the framework of hot deformations to model the creep behaviour of the powder material. The material behaviour of the container is modeled by incompressible plasticity via a power-law creep formulation. The extra constraints imposed in the axisymmetric approximation are eliminated by adapting suitable shape functions. The various material properties are assumed to be functions of temperature and relative density. The thermomechanical behaviour of powders is effectively modeled by a nonlinear transient heat transfer model, which is presented in the paper. A computational procedure for coupling the mechanical deformation with a thermal analysis is also addressed. The application of the present methodology is illustrated via the simulation of cylindrical powder metallurgy parts.

Recent developments in high speed HIP: R.M. Conaway, M. McKimpson, (Conaway Technologies, Dublin, Ohio, USA)

Hot isostatic pressing (HIP) techniques are being considered in the European Home Team as one of the fabrication routes to produce ITER-FEAT primary first wall panels (PFWP). To demonstrate the potential and the availability of such techniques, material development, innovative mock-up fabrications and numerical modeling for the production of near-net shape components are currently been studied by CEA/CEREM in collaboration with the EFDA-CSU Garching. The aim of this work is to investigate the manufacturing feasibility of advanced PFWP concepts, with reduced pitch between FW cooling channels and reduced material thickness between the FW cooling channels and the front surface, in order to improve the thermal fatigue performance of these concepts. In order to select the best fabrication route, two different manufacturing methods based on the HIP process are being considered. The first one consists in manufacturing of the first wall panel by a HIP forming technique. Mock-ups are made of a serpentine tube expanded into a proper matrix. 2-D computer modeling has been performed to estimate the serpentine deformation. The second manufacturing route is based on the powder HIP technique. Mock-ups have been made of a serpentine embedded into SS powder. In both cases, the objective was to obtain the minimum pitch between the stainless steel (SS) tubes and between the SS tubes and the front face.

Surface coatings as in-situ envelopes for hot isostatic pressing: D.J. Stephenson, et al, (Cranfield Institute of Technology, Cranfield, UK)

Hot isostatic pressing (HIP) techniques are being considered in the European Home Team as one of the fabrication routes to produce ITER-FEAT primary first wall panels (PFWP). To demonstrate the potential and the availability of such techniques, material development, innovative mock-up fabrications and numerical modeling for the production of near-net shape components are currently been studied by CEA/CEREM in collaboration with the EFDA-CSU Garching. The aim of this work is to investigate the manufacturing feasibility of advanced PFWP concepts, with reduced pitch between FW cooling channels and reduced material thickness between the FW cooling channels and the front surface, in order to improve the thermal fatigue performance of these concepts. In order to select the best fabrication route, two different manufacturing methods based on the HIP process are being considered. The first one consists in manufacturing of the first wall panel by a HIP forming technique. Mock-ups are made of a serpentine tube expanded into a proper matrix. 2-D computer modeling has been performed to estimate the serpentine deformation. The second manufacturing route is based on the powder HIP technique. Mock-ups have been made of a serpentine embedded into SS powder. In both cases, the objective was to obtain the minimum pitch between the stainless steel (SS) tubes and between the SS tubes and the front face.

Hot triaxial compaction (HTC) of particulates: H.R. Piehler, D.M. Watkins, (Carnegie-Mellon University, Pittsburg, USA)

Hot isostatic pressing (HIP) techniques are being considered in the European Home Team as one of the fabrication routes to produce ITER-FEAT primary first wall panels (PFWP). To demonstrate the potential and the availability of such techniques, material development, innovative mock-up fabrications and numerical modeling for the production of near-net shape components are currently been studied by CEA/CEREM in collaboration with the EFDA-CSU Garching. The aim of this work is to investigate the manufacturing feasibility of advanced PFWP concepts, with reduced pitch between FW cooling channels and reduced material thickness between the FW cooling channels and the front surface, in order to improve the thermal fatigue performance of these concepts. In order to select the best fabrication route, two different manufacturing methods based on the HIP process are being considered. The first one consists in manufacturing of the first wall panel by a HIP forming technique. Mock-ups are made of a serpentine tube expanded into a proper matrix. 2-D computer modeling has been performed to estimate the serpentine deformation. The second manufacturing route is based on the powder HIP technique. Mock-ups have been made of a serpentine embedded into SS powder. In both cases, the objective was to obtain the minimum pitch between the stainless steel (SS) tubes and between the SS tubes and the front face.

Effects of HIP consolidating temperature on mechanical properties of SiC whisker reinforced aluminium alloy composites

The effects of consolidating temperature in the strength, impact value, microstructure and fractography of SiC whisker reinforced 6061 and 5056 aluminium alloy composites were studied. The composites were fabricated using hot isostatic pressing of powders.

Modelling Shape Change of Parts Produced by Hot Isostatic Pressing of Powders

Models for analysing shape changes during the hipping of powder compacts enclosed in preshaped containers are presented. Two limiting mechanisms are considered: homogeneous densification and the mo ...

Processing Technology for Nickel Aluminides

AbstractDuctile ordered intermetallic alloys of nickel aluminum or nickel aluminum chromium have been developed at the Oak Ridge National Laboratory (ORNL) by optimized additions of boron. These alloys show excellent elevated temperature mechanical properties and corrosion properties. However, in order for the alloys to find use in various applications, they should be fabricable by either the well established or innovative processing technologies. The present paper will discuss the details of fabrication technology being pursued at ORNL. The processes being investigated include powder consolidation by extrusion, powder consolidation by capping, isothermal forging of powder compacted material, twin-roller casting to thin sheet followed by cold-rolling, direct casting rod from liquid, extrusion of billets made by argon-induction melting and electroslag remelting processes, injection molding of powders, and hot isostatic pressing of powders. Relative merits of each process will be discussed. Mechanical properties data on products made by various processes will also be presented and compared.

High Strength Co-Cr-Mo Alloy by Hot Isostatic Pressing of Powder

Currently available cobalt alloy prostheses for total hip applications are fabricated by investment casting techniques. Instances of stem fracture have been reported due to metal fatigue secondary to stem loosening or cement breakdown. A new process has been developed which includes the preparation of ultraclean powder and subsequent consolidation of the powder by hot isostatic pressing. The resultant solid material is characterized by 100 percent density and ultrafine grain size. Prostheses prepared by the new process have the same biocompatibility and corrsion resistance as the conventional cast alloy but higher strength and fatgue resistance.

Production and sealing of capsules for the hot isostatic pressing of powders

Production and sealing of capsules for the hot isostatic pressing of powders