To explore a novel high strength and low modulus ultralight-weight complex concentrated alloys (ULW-CCAs), a series of light alloys are designed and explored based on some low-density and low modulus elements, such as Al, Li, Mg, Ca, Si, and Y. An Al_19.9Li₃₀Mg₃₅Si₁₀Ca₅Y_0.1 (at %) CCA with a high specific strength of 327 KPa·m⁻³ is successfully developed. After adjusting the composition, the Al₁₅Li₃₅Mg₄₈Ca₁Si₁ CCA with the good compressive plasticity is successfully developed. The Al₁₅Li₃₈Mg₄₅Ca_0.5Si_1.5 and Al₁₅Li₃₉Mg₄₅Ca_0.5Si_0.5 CCAs exhibit good plasticity of >45%, and >60%, respectively. These ULW-CCAs show the high specific strength, good ductility, and low Young’s modulus, as compared with the previously reported CCAs.

The microstructural and mechanical properties of β-type Ti_85-xNb_10+xSn₅ (x = 0, 3, 6, 10 at.%) alloys with low elastic modulus were investigated. The experimental results show that the Ti₈₅Nb₁₀Sn₅ and Ti₇₅Nb₂₀Sn₅ alloys are composed of simple α and β phases, respectively; the Ti₈₂Nb₁₃Sn₅ and Ti₇₉Nb₁₆Sn₅ alloys are composed of β and α″ phases. The content of martensite phase decreases with the increase of Nb content. The Ti₈₂Nb₁₃Sn₅ and Ti₇₉Nb₁₆Sn₅ alloys show an inverse martensitic phase transition during heating. The Ti₈₅Nb₁₀Sn₅ and Ti₈₂Nb₁₃Sn₅ alloys with the small residual strain exhibit the good superelastic properties in 10-time cyclic loading. The reduced elastic modulus (E_r) of the Ti₇₅Nb₂₀Sn₅ alloy (61 GPa) measured by using the nanoindentation technique is 2–6 times of that of human bone (10–30 GPa), and is smaller than that of commercial Ti-6Al-4V biomedical alloy (120 GPa). The Ti₇₅Nb₂₀Sn₅ alloy can be considered as a novel biomedical alloy. The wear resistance (H/E_r) and anti-wear capability (H³/E_r²) values of the four alloys are higher than those of the CP–Ti alloy (0.0238), which indicates that the present alloys have good wear resistance and anti-wear capability.

The microstructure and mechanical properties of rapidly solidified β-type Ti–Fe–Sn–Mo alloys with high specific strength and low elastic modulus were investigated. The results show that the phases of Ti–Fe–Sn–Mo alloys are composed of the β-Ti, α-Ti, and TiFe phases; the volume fraction of TiFe phase decreases with the increase of Mo content. The high Fe content results in the deposition of TiFe phase along the grain boundary of the Ti phase. The Ti₇₅Fe₁₉Sn₅Mo₁ alloy exhibits the high yield strength, maximum compressive strength, large plastic deformation, high specific strength, high Vickers hardness, and large toughness value, which is a superior new engineering material. The elastic modulus (42.1 GPa) of Ti₇₅Fe₁₅Sn₅Mo₅ alloy is very close to the elastic modulus of human bone (10–30 GPa), which indicating that the alloy can be used as a good biomedical alloy. In addition, the large H/E_r and H³/E_r² values of Ti₇₅Fe₁₉Sn₅Mo₁ alloy indicate the good wear resistance and long service life as biomedical materials.