The present paper describes the manufacturing process of open-pore metal foams by investment casting and the mesostructural/morphological evolution resulting from a new technique of modifying the precursor. By this technique, the precursor is coated with a polymer layer whereby a thickening of the struts occurs. Relative densities in the range of1.85≤ρrel≤25%of open-pore metal foams can be achieved with high accuracy. The samples investigated have pore densities ofρP=7 ppi, 10 ppi, and 13 ppi. The relevant processing parameters needed for a homogenous formation of the polymer layer are determined for two different coating materials and the resulting open-pore foam’s mesostructure is characterized qualitatively and quantitatively. The alloy used for investment casting open-pore metal foamsis AlZn11. The microstructural evolution of these foams is evaluated as a function of the mesostructure. Differences in the microstructure are observed for foams with low and high relative densities and discussed in terms of cooling subsequent to investment casting.
This study presents a novel manufacturing process for open-cell stainless steel foams using a modified investment casting process and a novel approach to identify transitions between elastic-plastic, plateau, and densification region in the stress-strain history of compressed foams, based on its strain and structural hardening behavior. The influence of microstructure on the mechanical properties under quasi-static compression loading (plateau stress, energy absorption, and strain hardening) of austenitic (AISI 304, 316L) and super duplex (AISI F55) stainless steels is investigated. Microstructure is characterized prior and subsequent to mechanical testing using light microscopy and SEM. The manufacturing process yields open-cell foams with relative densities in the range of 14-20%, solid struts being circular in shape and defect-free surfaces. This morphology leads to improved yield strengths compared to open-cell steel foams produced by the powder metallurgical route. Among the manufactured open-cell steel foams, F55 foams with finegrained duplex microstructures show highest yield strength, strain hardening, and energy absorption with a sufficient ductility. Although a martensitic transformation is present in highly deformed struts of soft austenitic stainless steel foams, strain hardening in the plateau region is lower compared to duplex foams.
In the development of biocompatible synthetic materials for the surgery of bone fractures, open porous Ti foams have a high potential to find application as a geometrically and mechanically adaptable implant matrix. The present state of research mainly focuses on Ti foams produced using powder metallurgy, whereas cast manufacturing is barely investigated despite cast parts achieve higher mechanical strength and durability than those sintered. Therefore, the present study describes the manufacturing of Ti foam by precision casting using a centrifugal casting machine. Experimental investigations employed casting of CP-Ti grade 1 and grade 2 purity, and characteristics of this technique were ascertained and compared with the current proficiency in the field of dental research. The knowledge of specific influences on the feasibility of Ti foam manufacturing by precision casting – collated in this survey – enables specific optimization of the casting process as well as design enhancement relating to the cellular structure.
The present work explores the growing behavior of the intermetallic layer in the Mg-Si system. Following achievements have been obtained in our investigation: (i) A complete wetting concept is proposed for the lateral spreading of the intermetallic layer. (ii) In contrast to the stoichiometric property for the intermetallic phase in the phase diagram, the authors show that concentration gradients are able to be established in the kinetic process. (iii) Contrary to the reported growth behavior, d / t 0.25-0.5 in other intermetallics, the authors find a transition from d / ffiffi t p to d / t with an increase of the temperature, where d is the thickness of the intermetallic layer and t is the time.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.