Attenuation efficiency of X-ray and comparison to gamma ray and neutrons in composite metal foams

Steel–steel composite metal foams (S–S CMFs) and Aluminum–steel composite metal foams (Al–S CMFs) with various sphere sizes and matrix materials were manufactured and investigated for nuclear and radiation environments applications. 316 L Stainless steel, high-speed T15 steel and aluminum materials were used as the matrix material together with 2, 4 and 5.2 mm steel hollow spheres to manufacture various types of composite metal foams (CMFs). High-speed T15 steel is selected due to its high tungsten and vanadium concentration (both high-Z elements) to further improve the shielding efficiency of CMFs. This new type of S–S CMF is called high-Z steel–steel composite metal foam (HZ S–S CMF). Radiation shielding efficiency of all types of CMFs was explored for the attenuation of X-ray, gamma ray and neutron. The experimental results were compared with pure lead and Aluminum A356, and verified theoretically through XCOM and Monte Carlo Z-particle Transport Code (MCNP). It was observed that the radiation shielding effectiveness of CMFs is relatively independent of sphere sizes as long as the ratio of sphere-wall thickness to its outer-radius stays constant. However, the smaller spheres seem to be more efficient in general due to the fine fluctuation in the gray value profile of their 2D Micro-CT images. S–S CMFs and Al–S CMFs are respectively 275% and 145% more effective for X-ray attenuation than Aluminum A356. Compared to pure lead, CMFs show adequate attenuation with additional advantages of being lightweight and more environmentally friendly. The mechanical performance of HZ S–S CMFs under quasi-static compression was compared to that of other classes of S–S CMF. It is observed that the addition of high-Z elements to the matrix of CMFs improved their shielding against X-rays, low energy gamma rays and neutrons, while maintained their low density, high mechanical properties and high-energy absorption capability. - Highlights: • Composite metal foams (CMF) processed with various sphere sizes and matrix materials. • Samples were experimentally tested against X-ray, neutron and gamma. • High-Z elements in the matrix of CMFs improved their shielding effectiveness. • Experimental results were compared with numerical model. • High-Z elements did not degrade the mechanical performance of CMFs.