“…Typically, in these materials, the size, or at least the size distributions, of hollow fillers are deliberately set, while their relative position can range from arbitrary to ordered. Among them, metal matrix syntactic foams (MMSFs) are high-density foams produced with a metallic (Al [2][3][4][5], Mg [6][7][8][9], Zn [2,[10][11][12], Ti [13][14][15], or Fe [16][17][18][19][20] based) matrix and various types of porous fillers (hollow spheres [21] or other porous particles [22]) by molten metal infiltration [23,24]. MMSFs can be utilized as high-performance energy absorbers in vehicles [25] and defensive technologies [26], or as lightweight structural elements.…”