Novel approach for fabrication and characterisation of porosity-graded material

ABSTRACT

A novel continuously graded material that is based on a porosity-graded structure was successfully synthesised via a cold pressing-vacuum sintering-dissolution process (SDP) of powder metallurgy technology. Microscopic observations and the Archimedes method were used to confirm the newly synthesised porosity-graded material, the mechanical properties and the modulus. The results show that the density continuously increased from 1.4 to 2.7 g cm⁻³, and there was no obvious interfacial transition layer. In addition, the hardness and elastic modulus were obtained from nanoindentation tests and display a stepwise feature along the gradient direction. Moreover, we found that the fractography changes from typical ductile fracture to ductile and cleavage fracture with an increase in the porosity.

Highlights

• A porosity graded material has been successfully synthesised by powder metallurgy.

• The density continuously transit from 1.4 to 2.7 g cm⁻³, and it has no obvious interfacial transition layer.

• The stepwise feature of density and modulus shows great potential in the shields of spacecrafts.

GRAPHICAL ABSTRACT

KEYWORDS:

• Porosity-graded structure
• powder metallurgy
• porosity-graded material
• interfacial transition layer
• modulus
• mechanical properties
• density
• hardness
• elastic modulus

Acknowledgements

The authors thank Prof. Ma and Prof. Liu for the instructive suggestions and valuable comments on the writing of this article.

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Yang Liu http://orcid.org/0000-0003-2553-9515

Additional information

Funding

The research reported in this paper was financially supported by the National Basic Research Program of China (No. 61xxxx02).