开孔泡沫钛力学性质的温度相依性

Temperature-Dependence of Mechanical Properties of Open-Cell Titanium Foam

用粉末烧结法制备了相对密度为0．2的开孔泡沫纯钛材料，并在室温20～600℃温度范围内，对其压缩性能进行了测试，并从理论上分析了其杨氏模量、弹性极限和屈服强度对温度的相依性。结果表明：该开孔泡沫材料在室温下表现出脆性泡沫材料变形断裂特征；在200℃以及更高温度下，该材料表现出塑性开孔泡沫材料变形特征，其应力-应变曲线分为3个阶段，即弹性阶段，平台阶段和压实阶段。开孔泡沫钛的杨氏模量、弹性极限和屈服强度随着温度的升高而减小，其对温度的相依性可分别表示为：E^＊=1．5217×10^9-5．988×10^5 T，σel^＊=85．7-0．095T，σys^＊=99．1-0．16T＋7．02×10^-5T^2。

An open-cell titanium foam with relative density of 0.2 was prepared by powder metallurgical process. The compressive mechanical properties of the foam at the different temperatures in the range of 20-600 ℃ were measured and the temperature-dependence of its mechanical properties was discussed. The results indicate that the foam material exhibit fragile fracture characteristic at room temperature. When it is deformed over 200 ℃, the stress-strain curves exhibit plastic deformation characteristic, including three distinct regions： the linear elasticity region, the plastic collapse region, and the densification region. The Young＇s modulus, yield stress and elastic limit decrease with increasing of temperature. The temperature-dependence of these properties can be expressed as E^＊= 1.5217 × 10^9-5.988 × 10^5 T, σel^＊ =85.7-0.095T, σys^＊=99.1-0.16T＋7.02^-5 T^2 respectively.