Cold Spray Tensile Strength Literature Review

of two

Cold Spray Technique Studies

Tantalum-Based High Pressure Cold Spray (2019), Micro-Forging Assisted Cold Spray (2018), and Ni-based Braze Alloy in Cold Spray (2018) are 3 studies showing cold spray techniques that improved tensile strength. Further details on each study are presented below.

Title: Tantalum Based High-Pressure Cold Spray Coatings on Stainless Steel Substrate

  • The researchers of this study are "Jagannadh V.S.N. Sripada, Media F. Gallant, Gobinda C. Saha, and Reeti Singh, Jan Monday". It was published in the Key Engineering Materials Vol. 813, and has been available online since July 2019.
  • Tantalum (Ta) was chosen in the research as the feedstock coating to be deposited on AISI 1018 carbon steel substrate using the high-pressure cold spray (HPCS) method.
  • Tantalum's properties include good resistance to corrosion, good ductility, and notable hardness. It is also known for its high heat resistance, heat conductivity, and electrical conductivity.
  • The cold spray coating technology allows the deposition of powder feedstock, such as Tantalum, without melting. As the feedstock powder is propelled through a nozzle using high velocities, they plastically deform upon impact, causing a good bond with the substrate.
  • This study aimed to achieve a "dense and nonporous coating microstructure" with high efficiency in terms of deposition.
  • As a result, the material created after coating the stainless steel substrate with Tantalum exhibited an ultimate tensile strength of 442 MPa and 77 MPa adhesion strength.

Title: Deposition behavior, microstructure and mechanical properties of an in-situ micro-forging assisted cold spray enabled additively manufactured Inconel 718 alloy

Title: Strategy of incorporating Ni-based braze alloy in cold sprayed Inconel 718 coating

  • This research study was conducted by Wen Sun, Ayan Bhowmik, Adrian Wei YeeTan, Fei Xue, Iulian Marinescu, Feng Li, and Erjia Liu. Their study was published in Surface abd Coatings Technology, Vol. 358 on January 2019.
  • A high-pressure cold spray process was performed to deposit Ni-based superalloy (Inconel 718) and Ni-based braze alloy (MAR-M 002) composite coatings on the Inconel 718 substrate.
  • The researchers found that the Mar-M 002 particles were uniformly distributed within the composite coatings and was successfully embedded in the substrate via cold spraying.
  • Heat treatment after the cold spray deposition was also conducted as part of the strategy of incorporating the composite coatings.
  • The heat treatment process also reduced the coating porosity as it enhances the chemical diffusion between Inconel 718 and MAR-M 002 particles.
  • The results also showed the heat-treated material with composite coatings of Inconel 718 and MAR-M 002 had about 810 MPa tensile strength, which is 17% higher than the heat-treated pure Inconel 718 coating.
  • The study shows that the method of forming Inconel 718/MAR-M 002 composite deposits through cold spraying and post-heat-treatment improves the interparticle bond strength in the deposits.
of two

Cold Spray Best Practices

Due to the lack of publicly available information, we could not find any recommended best practices reinforcing cold-sprayed materials to achieve high levels of tensile strength. Helpful findings are detailed below.
  • Cold spray deposition provides the "possibility of obtaining almost zero-porosity buildups with no theoretical limit to the thickness."
  • Cold spray can also get rid of evaporation, particle melting, crystallization, unwanted oxidation, grain growth, undesirable phases and thermally induced tensile residual stresses.
  • According to research, cold spray technique can be utilized "as a complementary additive manufacturing method for fabrication of high-quality freestanding components where higher deposition rate, larger final size and lower fabrication temperatures are desired."
  • According to a report by Arbegast Materials Processing and Joining Lab, the 2 cold spray process system configurations are high-pressure and low-pressure systems.
  • One test method used for bond strength or tensile stress in cold spray technique is the ASTM C633 test method, or more specifically the ASTM Standard C 633-01 which uses a tensile testing machine to pull rods and eliminate any forces from bending.
  • ASTM International is a world recognized leader in the delivery and development of voluntary consensus standards, including the cold spray method.
  • ASM Thermal Spray Society, founded in 1994, is a global organization with "approximately 1,500 individuals around the globe representing over 500 leading companies, research institutions and universities."

Research Strategy:

Due to the lack of publicly available information, we could not find any recommended best practices reinforcing cold-sprayed materials to achieve high levels of tensile strength. To search for the required information, we employed 3 research strategies detailed below:

First, we researched for pre-compiled information and reports about best practices reinforcing cold-sprayed materials from well-known and renowned international associations such as ASTM International and ASM Thermal Spray Society as the most credible sources of information regarding standards in materials processing and cold spray techniques. However, we did not find any best practices documents or articles. We only found information about the associations and a cold spray handbook which is hidden behind paywall.

Second, we then scanned research papers and report sources such as ResearchGate, Science Direct, and Scientific. We searched for any research papers or reports about best practices reinforcing cold-sprayed materials to achieve high levels of tensile strength. However, we still did not find any best practices addressing the question. We only found research papers about the usage and applications of cold spray methods.

Third, we tried to triangulate for any data and statistics by searching from different industry reports surrounding the applications of cold spray method from industry sources such as South Dakota School of Mines & Technology, Asbin Industries, Strategic Environmental Research and Development Program (SERDP), and the Association of Aerospace Industries. However, we still did not find any best practices reports or articles to directly address the question. We only found a report about cold spray method which includes information about benefits and advantages, but no best practices.

Due to lack of pre-compiled reports, we therefore concluded that there is no publicly available data regarding best practices reinforcing cold-sprayed materials to achieve high levels of tensile strength. We only found helpful findings such as applications of cold spray methods, common test methods used to test the tensile strengths during the cold spray technique, and paywall handbook about cold spray method.

From Part 01
  • " In this research, Tantalum is deposited on stainless steel substrate using high-pressure cold spray (HPCS) method."
  • "Mar-M 002 particles were successfully embedded in IN718 deposits via cold spraying."
  • "The heat-treated Inconel 718/MAR-M 002 composite coating had a tensile strength of about 810 MPa that was about 17% higher compared to the heat-treated pure Inconel 718 coating."