Influence of mean grain size with ultrasonic velocity on microhardness of B4C–Fe–Ni composite

Ahlatçı

Journal of Composite Materials

2023

In this study, microstructure, mechanical, tribological and corrosion properties of boron carbide (B4C) and carbon nanotubes (CNT) reinforced hybrid AISI 316L stainless steel matrix nanocomposites were investigated. The AISI 316L stainless steel alloy and 316L-1B4C-1CNT (vol%), 316L-2B4C-2CNT (vol%), 316L-4B4C-4CNT (vol%) composites were fabricated by hot pressing under vacuum conditions. The fabricated samples showed minor porosities regardless of the concentration of B4C and CNT. Microstructure investigations revealed that a slight grain refinement was achieved with increasing incorporation of B4C and CNT. Furthermore, Fe3C and Cr23C6 intermetallics progressively formed along the grain boundaries in the hybrid composites. The hardness, compressive yield strength and wear resistance of 316L stainless steel exhibited continuous improvement with increasing additions of B4C and CNT. However, the hybrid composites exhibited higher susceptibility to pitting corrosion.

Section: Resultsmentioning

confidence: 99%

“…In addition, the presence of hard reinforcing elements such as B 4 C and CNT in proportion to soft 316L matrix also plays an important role in the increase in hardness. 21 It is also noteworthy that the formation of Fe were prevented more effectively in the CNT reinforced composites, causing the hardness to be higher in these composites. Nevertheless, the hardness of 316L stainless steel can be enhanced to comparable levels more costeffectively by the synergistic effects of CNT and B 4 C.…”

Section: Mechanical Propertiesmentioning

confidence: 99%

Production and characterization of AISI 316L stainless steel matrix hybrid composites reinforced with boron carbide and carbon nanotubes

Ahlatçı

Journal of Composite Materials

2023

“…Currently, ultrasonic nondestructive evaluation is based on analyzing the characteristics of ultrasound from the inspected object, including wave speed, ultrasonic attenuation, and diffuse backscatter results. For example, the longitudinal wave velocity was used to estimate the yield strength of the duplex stainless steel with different ferrite fractions as well as the mean grain size of metal matrix composites at different sintering temperatures [ 11 , 12 ]. Papadakis stated that the attenuation in polycrystalline materials could be classified as Rayleigh scattering, random scattering, and diffuse scattering according to the frequency and average grain size [ 13 ].…”

Section: Introductionmentioning

confidence: 99%

Anisotropy Evaluation and Defect Detection on Laser Power Bed Fusion 316L Stainless Steel

Peng

Liu

et al. 2023

Micromachines

Because of rapid heating, cooling, and solidification during metal additive manufacturing (AM), the resulting products exhibit strong anisotropy and are at risk of quality problems from metallurgical defects. The defects and anisotropy affect the fatigue resistance and material properties, including mechanical, electrical, and magnetic properties, which limit the applications of the additively manufactured components in the field of engineering. In this study, the anisotropy of laser power bed fusion 316L stainless steel components was first measured by conventional destructive approaches using metallographic methods, X-ray diffraction (XRD), and electron backscatter diffraction (EBSD). Then, anisotropy was also evaluated by ultrasonic nondestructive characterization using the wave speed, attenuation, and diffuse backscatter results. The results from the destructive and nondestructive methods were compared. The wave speed fluctuated in a small range, while the attenuation and diffuse backscatter results were varied depending on the build direction. Furthermore, a laser power bed fusion 316L stainless steel sample with a series of artificial defects along the build direction was investigated via laser ultrasonic testing, which is more commonly used for AM defect detection. The corresponding ultrasonic imaging was improved with the synthetic aperture focusing technique (SAFT), which was found to be in good agreement with the results from the digital radiograph (DR). The outcomes of this study provide additional information for anisotropy evaluation and defect detection for improving the quality of additively manufactured products.

Proceedings of the 2016 7th International Conference on Mechatronics, Control and Materials (ICMCM 2016)

“…Ultrasonic attenuation coefficient is sensitive to the average grain size, the grain size increases; the attenuation coefficient increases [4,5,6,7,8]. Sound velocity is affected by grain binding force and residual stress, and is sensitive to content of precipitate [9], precipitated phase [4], phase change [10,11].…”

Section: Introductionmentioning

confidence: 99%

Influence of heat treatment on the microstructure, ultrasonic attenuation and ultrasonic velocity of GH4169 alloy

Chen¹,

Zhou²,

Wu³

2016

Abstract. Microstructural changes in GH4169 alloy due to changes in annealing temperature are characterized by ultrasonic pulse-echo technique and optical microscopy. According to differential thermal analysis, the phase-transition temperature of GH4169 is 1022℃. GH4169 alloy are heat treated at different temperature for 60 min, and water quenched. Ultrasonic velocities and attenuation coefficient of ultrasonic waves produced with 10 MHz transducers were evaluated for these heat-treated samples by pulse-echo method. The microstructural changes with phase-transition temperature are correlated to the ultrasonic characteristics of the alloy.