Crystal structures and hardness of novel compounds: Hexagonal Mo(CuxAl1−x)6Al4, MoCu2Al8−x and orthorhombic {Mo,W,Re}Ni2−xAl8+x

► Mo(CuxAl1−x)6Al4 can be considered as an unfilled variant of the MgFe6Ge6 type. ► Phase equilibria at 930 °C for the Al-rich region of the W-Ni-Al phase diagram were reported. ► Vicker's hardness for the isotypic compounds {Mo,W,Re}Ni2−xAl8+x reveal the highest hardness of HV = 965 ± 25 MPa.