Acoustic Properties of 316L Stainless Steel Hollow Sphere Composites Fabricated by Pressure Casting

Chunhe Wang,Chunhuan Guo,Shuaiqi Shao,Fengchun Jiang,Tianmiao Yu

doi:10.3390/met10081047

Abstract

In this study, we prepared metal hollow sphere composites (MHSCs) using metal hollow spheres (MHSs) by pressure casting under vacuum conditions, and investigated the acoustic properties. The density of the MHSCs was measured using the mass to volume ratio, the microstructure of the MHSCs was observed using a scanning electron microscope, and the acoustic properties of the MHSCs were tested using an impedance tube. The measured MHSCs showed that the densities of the MHSCs with the random distribution of MHSs with diameter ~3.28 mm (1.74 g/cm3 to 1.77 g/cm3) (MHSC-3.28) were nearly equal to that of the MHSCs with the random distribution of MHSs with diameter ~5.76 mm (1.74 g/cm3 to 1.76 g/cm3) (MHSC-5.76), and lower than that of the MHSCs with the layered structure of MHSs with diameter ~3.28 mm (1.93 g/cm3 to 1.97 g/cm3) (MHSC-LS). Microstructural observations confirmed that the interface region between the MHSs and matrix demonstrated a simple physical combination pattern with pores. The acoustic properties of the MHSCs showed that the sound absorption coefficient of MHSC-LS was lower than that of MHSC-3.28 and higher than that of MHSC-5.76 at off-resonance. The sound absorption coefficient peak value of MHSC-3.28 was higher than that of MHSC-LS, and lower than that of MHSC-5.76 at resonance. The sound transmission loss of MHSC-3.28 was lower than that of MHSC-5.76, which shows the rules are independent from the resonance. The sound transmission loss of MHSC-LS was higher than that of MHSC-5.76 at resonance, but lower than that of MHSC-3.28 at off-resonance. In addition, we discuss the propagation mechanism of the sound waves in the MHSC, which is mainly determined by the distribution of the MHSs in the MHSC.

Highlights

In the second decade of the 21st century, the industry dictated a number of requirements for multi-functional materials, which provided new challenges in the field of materials science
From the results of metal hollow sphere composites (MHSCs)-3.28 and MHSC-5.76, found that the sound transmission increased results of MHSC-3.28 and MHSC-5.76, we found that the sound transmission loss increased gradually
We studied the physical properties, microstructure, and the acoustic properties of the MHSCs

Summary

Introduction

In the second decade of the 21st century, the industry dictated a number of requirements for multi-functional materials, which provided new challenges in the field of materials science. Properties that appear incompatible at first glance, such as high strength, sound insulation, heat resistance, and fire resistance, and at the same time low density, should be combined in one material to meet the growing requirements of the automotive, aerospace, and marine industries [1]. Responding to this challenge, modern science has paid attention to the study of materials, such as syntactic foams containing hollow spherical objects.

Methods

Results

Discussion

Conclusion