Spray forming

About: Spray forming is a research topic. Over the lifetime, 1153 publications have been published within this topic receiving 12869 citations. The topic is also known as: spray casting & spray deposition.

Superplastic deformation behavior of a spray-deposited eutectic NiAl/Cr(Mo) alloy doped with Dy

Abstract: The tensile deformation behavior at elevated temperatures and the associated mechanisms are investigated for hot isostatically pressed NiAl-28Cr-5.9Mo-0.1Dy fabricated through spray forming. Superplasticity is observed at above 1323 K under an initial strain rate lower than 10−3 s−1 with an m value of 0.5. The activation energies for superplastic flow are found to be half of that for self-diffusion in NiAl. Grain boundary sliding between NiAl and adjacent NiAl or Cr(Mo) grains with local range accommodation, i. e., dynamic recovery, is suggested to be responsible for the superplastic deformation of the alloy.

Study of the Effect of Hot Gas on Atomization Quality of Spray Forming

Abstract: In the spray forming process, the atomizing quality is not very good under the low pressure. This article attempts to improve the quality of atomization through heating the gas. A mathematical model is built and calculated according to the existing knowledge, and then the influence of airflow temperature in the spray forming is theoretical calculated and analyzed. The experimental results show that the average grain size is 54μm when the gas is not heated; the average grain size is 39 μm which decreases by 27.7% than airflow unheated when the gas is heated to 150 °C. The calculation results show that when the gas is not heated, the first time atomization grain size is 201 μm, the second time atomization grain size is 15 μm, the total atomization time is 92 μs. And the velocity of atomization droplets is 80 m/s; when the airflow temperature is 150°C, the above results are 131 μm, 10 μm, 76 μs and 127 m/s respectively, the atomization quality has a certain improvement compared to the unheated condition. At the same time, the grain shape becomes more round as the temperature of airflow increases, and the holes between the grains also become smaller.

Effect of Spray Pressure and Height on Interfacial Heat Transfer of H13 Steel during Spray Cooling

Abstract: accurately calculate mold temperature field during spray process of die casting process, the interfacial heat transfer coefficient (IHTC) between the mold and the spray medium is an extremely important thermo-physical parameter. In this paper, a spray experiment was conducted with different spray pressures and heights, in which the temperature history throughout the spray cooling process of H13 steel plate was recorded. The IHTC under the different spray parameters were calculated by utilizing the nonlinear estimation method. The interface morphology and heat transfer characteristics within the spray cooling process were studied, and the influence of spray pressures and heights on the IHTC was discussed. The results show that the interface can be divided into wet and dry regions, where the former significantly affects the heat transfer behavior on the interface. It is found that high spray pressure has a positive effect on improv-ing peak IHTC whereas it impedes the expansion of wet region and delays the peak of IHTC; reducing spray height leads to the expansion of wet region and the rise of peak IHTC.

Simulation of metal droplet events during gas horizontal atomization stage in the spray rolling of 7050 aluminum alloy

Abstract: Spray rolling is a novel metallic semi-solid near-net-shape forming technology. This paper describes the qualitative influence of the key process parameters on the history of velocity, dynamic behavior and enthalpy of the gas and atomized droplets in spray rolling of 7050 alloy based on the fundamentals of spray forming and twin-casting. Results show that the process parameters such as flight time, gas initial velocity, droplet diameter, metal mass flow rate have remarkable influence on process performance including the heat transfer coefficient, droplet velocity, temperature, and solid fraction. This work provides a method to better understand the spray rolling technology.