Patent Application
20230078467
The present disclosure relates to extrusion assemblies and methods. Particular embodiments include shear-assisted extrusion assemblies and methods that can be used to create multi-metallic materials.
Co-extrusion via hydrostatic extrusion and indirect extrusion is either expensive or results in non-uniform material flow. Furthermore, elaborate billet fabrication steps, requirement of specific area ratio between core and the sleeve, difficulty in co-extruding 1100 and 7075Al, and billet preheating are typically employed to obtain desirable bonding at the interface. Thermal spray coatings are limited to thin coatings which might not be beneficial for long-term applications due to cracking and spallation, and explosive bonding has safety and material constraints.
A few research level solutions that can never be applied at a manufacturing scale are fabrication of bi-metallic laminates using equal channel angular pressing and/or high pressure torsion.
Therefore, for increased energy efficiency and reduced plant downtime due to repair, an alternate manufacturing approach is required to fabricate the multi-metallic tubes with relative ease and better interface properties.
Shear-assisted extrusion assemblies are provided. The assemblies can include: a billet assembly containing a billet comprising a billet outer material and a billet inner material in at least one cross-section; a tool operably engaged with the billet; an extrudate receiving channel configured to receive extrudate from the tool, wherein the extrudate comprises extruded outer material and extruded inner material in at least one cross-section, the extruded outer material being the same material as the billet outer material, and the extruded inner material being the same as the billet inner material.
Methods for producing a multi-material shear-assisted extrudate are also provided. The methods can include: providing a billet comprising billet inner material and billet outer material; providing shear-assisted force to a tool operably engaged with the billet to form an extrudate comprising extruded inner material and extruded outer material wherein the extruded outer material is the same material as the billet outer material, and the extruded inner material being the same as the billet inner material.
Embodiments of the disclosure are described below with reference to the following accompanying drawings.
This disclosure is submitted in furtherance of the constitutional purposes of the U.S. Patent Laws “to promote the progress of science and useful arts” (Article 1, Section 8).
The present disclosure will be described with reference to
The materials (inner, outer, intermediate) that make up the extrudate can have distinct chemical and/or mechanical properties. For example, co-extrusion of 6061 (shell) and 7075 (core), 1100 (shell) and 7075 (core), and 1100 (shell) and 2024 (core) was performed to complete extrudates having commensurate outer and inner materials having sound bonding at the interface. Furthermore, thickness of the sleeve and core can be controlled via the area ratio of the constituent billet material. Multi-metallic tubes can be fabricated utilizing a tool that engages a mandrel.
The ShAPE process works in billet area ratio of ⅓ and ⅔, and also ½ and ½ leading to the tube thickness of ⅓ and ⅔, and ½ and ½, respectively. Based on the current observations, a much thinner core/sleeve, preferably having ¼ of the tube thickness is quite possible. Therefore, either a thicker or thinner coating can easily be fabricated. Temperature control of the process using the shear and friction parameters can provide for more flexible fabrication of multi-metallic components having significantly different flow stresses. Furthermore, multi-metallic extrudate tubes exhibiting variable thicknesses can be fabricated by controlling the billet stack with minimal effort in billet fabrication. This allows for joining the b metallic tubes to other structures so that easily weldable material of necessary thickness is the sleeve. Difficult to extrude material combination such as 1100 and 7075/2024 Al can easily be co-extruded.
Furthermore, these multi-metallic extrudates, having gone through high temperature severe plastic deformation, can be aged without solutionizing or annealing heat treatments, thereby thermal stresses and the subsequent dimensional instability can be avoided and/or grain growth minimized.
Referring to
Tool 14 can be retained within tool holder 21 and operably engaged with billet material 20 to create a high shear region 26 at die face 28. As shown, a rotational force and axial force is applied to die face 28 of tool 14. The axial force may be applied from the tool upon the feed material; alternatively, the axial force may be applied from the feed material upon the tool. In accordance with example implementations, the shear assisted extrusion process will provide an extrudate 18. Mandrel 16 can be anchored in billet holder assembly 12 and extend through billet material 20 and die face 28 to extrudate receiving channel 11.
This application is related to U.S. Continuation-In-Part patent application Ser. No. 17/473,178 filed Sep. 13, 2021, entitled “Devices and Methods for Performing Shear-Assisted Extrusion and Extrusion Processes”. the entirety of which is hereby incorporated by reference herein.
Referring to
Referring to
Referring to
Accordingly, billet containing assembly 12 containing a billet that includes a billet outer material 22b and a billet inner material 24b in at least one cross-section. The billet 20 can also include a billet intermediate material 90b between billet inner material 22b and billet outer material 24b in the at least one cross-section. The assembly can include mandrel 16 extending from billet containing assembly 12 to tool 14. Mandrel 16 can extend through an opening in die face 28 of the tool 14. Billet material 20 can also include a billet boundary material 40b directly adjacent and/or lateral of either billet inner material 22b or outer material 24b. the billet boundary material is the same material as the billet outer material. Billet boundary material 40b can be a different material than either or both of the billet inner material 22b or outer material 24b. In at least one cross-section the thickness of one or more of the inner 22e, outer 24e, and/or intermediate 90b billet materials is different. Each material thickness can be as low as a 10th of the thickness of the material directly adjacent thereto. In billet container assembly 12, the billet materials can be unbound.
The extrudate 18 can also include extruded intermediate material 90e between extruded outer material 24e and extruded inner material 22e in the at least one cross-section.
In accordance with the above assemblies, the methods can include a billet intermediate material 90b between the billet inner material 22b and billet outer material 24b. Billet intermediate material 90b can be a single material or multiple different materials. Inner 22b and outer 24b billet material can be about the same thickness in at least one cross-section. Extruded inner 22e and outer 24e materials can be about the same thickness in at least one cross-section. Inner billet material 22b can be 1/10 to 9/10 the thickness of outer 24b billet material. Extruded inner material 22e can be 1/10 to 9/10 of the thickness of extruded outer billet material 24e. The extruded materials define bonded interfaces between different and previously unbound billet materials.
As an example method with reference to Table 1 below, multi-metallic extrudates were prepared. These parameters are not limiting and ranges of rotational speed as well as advance rate can be utilized.
The extruded tubes were sectioned for various microscopy and mechanical property characterizations in as-extruded condition. For optical and scanning electron microscopy (SEM) analysis, the tubes were sectioned along both longitudinal and transverse cross-sections. The cut samples were mounted in an epoxy, polished to a surface finish of 0.05 μm using colloidal silica suspension, and etched using Keller's reagent. Both stereo and light microscopy (in bright field mode) analyses of the samples were carried to analyze the tube quality and interface characteristics. The samples were repolished to 0.05 μm surface finish for SEM and energy-dispersive X-ray spectroscopy (EDS) analysis. SEM in back scattered electron (BSE) mode and EDS analyses of the cladded tubes and the interface between 1100/7075 Al, and 1100/2024 Al were completed using the FEI Quanta 3D field emission gun dual beam FIB/SEM. Vickers hardness measurements in as-extruded was carried out using Clark Microhardness tester CM-700AT and five indents per sample was done. Tensile testing of 127 mm (5″) long tubes was carried out in accordance with ASTM-B557 standard. All the results and discussion are presented in the next section.
Referring to
The measured tool temperature (° C.) and the spindle torque (Nm) as a function of plunge depth for both the extrusions is presented in
Steady-state temperatures in 1100/7075 Al and 1100/2024 Al were about 380 and 390° C., respectively, mainly due to slightly lower rotational speed in the former extrusion. An initial transition in spindle torque was also noted (
Referring next to
Overall, the presence of metallurgically bonded interface obtains cladded tubes with good structural integrity.
Referring next to
In accordance with an example implementation, at least a pair of billet designs are shown in
Successful extrudate fabrication of distinctly different flow strength materials can provide heat exchangers with high temperature strength materials having a corrosion/oxidation resistance material as either an inner or outer material. At least one example of this application is co-extrusion of copper-nickel bi-metallic tubing which has been performed using these methods. Moreover, the apparatus and methods described herein enable continuous cladding from start to stop. For example, the outer material can be present over an entirety of an extrudate surface. Additionally, or alternatively, the apparatus and method provide the ability to vary or change outer material thickness. That is, a thicker and/or thinner outer material may be continuously fabricated along an outer surface of the extrudate.
In compliance with the statute, embodiments of the invention have been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the entire invention is not limited to the specific features and/or embodiments shown and/or described, since the disclosed embodiments comprise forms of putting the invention into effect. The invention is, therefore, claimed in any of its forms or modifications within the proper scope of the appended claims appropriately interpreted in accordance with the doctrine of equivalents.
This application claims priority to and the benefit of U.S. Provisional Patent Application Ser. No. 63/244,632 filed Sep. 15, 2021, entitled “Co-Extrusion/Cladding of Dissimilar AL Alloys Via Shear Assisted Processing and Extrusion”, the entirety of which is incorporated by reference herein.
This invention was made with Government support under Contract DE-AC05-76RL01830 awarded by the U.S. Department of Energy. The Government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63244632 | Sep 2021 | US |
