- 钛的十大特性
I. Ten properties of titanium
◆ 密度小,比强度高： 金属钛的密度为4.51g/cm3,高于铝而低于钢、铜、镍，但比强度位于金属之首。
◆Low density, high specific strength: Titanium’s density is 4.51g/cm3, higher than that of aluminum, while lower than that of steel, copper and nickel, but its specific strength tops all metals’.
◆ 耐腐蚀性能： 钛是一种非常活泼的金属，其平衡电位很低，在介质中的热力学腐蚀。但实际上钛在许多介质中很稳定，如钛在氧化性、中性和弱还原性等介质中是耐腐蚀的。
◆ Corrosion resistance: Titanium is a kind of very active metal with low equilibrium potential and strong trend of thermodynamic corrosion in media. But, in fact, titanium is very stable in many media; take its corrosion resistance in oxidant, neutral and weak reducing and so kinds of media for instance.
◆ 耐热性能好： 新型钛合金可在600℃或更高的温度下。
◆ Good heat resistance: New titanium alloy can be used for a long term under the temperature of 600℃, or more.
◆ 耐低温性能好： 钛合金TA7（Ti-5Al-2.5Sn）,TC4(Ti-6Al-4V)和Ti-2.5Zr-1.5Mo等为代表的低温钛合金,其强度随温度的降低而提高,但塑性变化却不大。在-196-253℃低温下保持较好的延性及韧性,避免了金属冷脆性,是低温容器,贮箱等设备的理想材料。
◆ Preferable resistance to low temperature: With titanium alloy TA7Ti-5Al-2.5Sn）, TC4(Ti-6Al-4V) and Ti-2.5Zr-1.5Mo and so forth as representatives of low-temperature titanium alloy, its strength grows as temperature decreases, but its plasticity doesn’t change so much. Under the low temperature of -196-253℃, it maintains preferable ductility and tenacity and avoids metals’ cold brittleness. It is the perfect material for equipments, such as, low temperature vessels and conduit heads.
◆ 抗阻尼性能强： 金属钛受到机械振动、电振动后，与钢、铜金属相比，其自身振动衰减时间最长。
◆ Strong antidumping property: When titanium is affected by mechanical vibration or electric oscillation, its vibration damping time lasts the longest time, compared to that of steel and copper.
◆ 无磁性、无毒： 钛是无磁性金属，在很大的磁场中也不会被磁化，无毒且与人体组织及血液有好的相溶性，所以被医疗界采用。
◆ Nonmagnetic and non-toxic: Titanium is a kind of nonmagnetic metal, even in a very big magnetic field, cannot be magnetized. It is non-toxic and has a good intermiscibility with people’s tissue and blood, so is adopted by medical field.
◆ 抗拉强度与其屈服强度接近：钛的这一性能说明了其屈强比（抗拉强度/屈服强度）高，表示了金属钛材料在成形时塑性变形差。由于钛的屈服极限与弹性模量的比值大，使钛成型时的回弹能力大。
◆ Tensile strength almost parallels yield strength: Titanium’s this property proves its high yield ratio (tensile strength/ yield strength), and indicates its poor plastic deformation in taking shape. Its resilience is strong during shaping, because titanium’s ratio of yield limit to elasticity modulus is high.
◆ 换热性能好：金属钛的导热系数虽然比碳钢和铜低，但由于钛优异的耐腐蚀性能，所以壁厚可以大大减薄，而且表面与蒸汽的换热方式为滴状冷凝，减少了热组，太表面不结垢也可减少热阻，使钛的换热性能显著提高。
◆ Efficient heat exchange performance: Due to titanium’s excellent corrosion resistance, the thickness of wall can be extremely deduced; the heat exchange mode between its surface and steam is droplet condensation and its surface has no scale formation, so heat resistance is decreased; all these help improve titanium’s heat exchange performance, though its coefficient of heat conductivity is lower than that of carbon steel and copper.
◆ 弹性模量低：钛的弹性模量在常温时为106.4GMPa,为钢的57%。
◆ Low elasticity modulus: At normal temperature, titanium’s elasticity modulus is 106.4GMPa, 57% of that of steel.
◆ 吸气性能：钛是一种化学性质非常活泼的金属,在高温下可与许多元素和化合物发生反应。钛吸气主要指高温下与碳、氢、氮、氧发生反应。
◆ Sorption property: Titanium is a kind of metal with very active chemical property. In high temperature, it can react with many elements and compounds. Titanium sorption mainly refers that it reacts with carbon, hydrogen, nitrogen or oxygen in high temperature.
二、钛的三大功能
Ⅱ. Three main functions of titanium
功能材料是以物理性能为主的工程材料，即在电、磁、声、光、热等方面具有的特殊性质，或在其作用下表现出特殊功能的材料。对钛和钛合金的研究已发现其有三种特殊功能有应用前途:
Functional materials refers to engineering materials exhibiting physical properties mainly, namely, the special properties existing in aspects, such as, electricity, magnetism, sound, light, heat, or materials exhibiting special properties effected by them. The research in titanium and its alloy has found it has three special functions which has promising application future.
1.记忆功能：钛-镍合金在一定环境温度下具有单向、双向和全方位的记忆效应，被公认是最佳记忆合金。在工程上做管接头用于的油压系统；石油联合企业的输油管路系统；直径0.5mm丝做成的直径500mm抛物网状天线用于宇航飞行器上；在医学工程上用于制作鼾症治疗；制成螺钉用于骨折愈合等。上述应用均获得了明显 效果。
1. Memory function: In certain ambient temperature, titanium-nickel alloy has the function of one-way, two-way and omnibearing memory effects, so it is concerned to be the best memory alloy. It proved to have positive effect in the following fields: In engineering, it is made into tube union for oil hydraulic system of fighters, oil transportation pipeline system in petroleum complex, parabolic net antennas with the diameter of 500mm made from its wire with a diameter of 0.5mm for aerospace vehicles; in medical engineering, it is used to treat snoring disease; made into screws for fracture healing, etc..
2.超导功能：铌-钛合金在温度低于临界温度时，呈现出零电阻的超导功能。
2. Superconducting function: Niobium-titanium alloy demonstrates superconducting function of zero resistance when it is lower than critical temperature.
3.贮氢功能：钛-铁合金具有吸氢的特性，把大量的氢安全的贮存起来，在一定的环境中又把氢释放出来。这在氢气分离、氢气净化、氢气贮存及运输、制造以氢为能源的热泵和蓄电池等方面应用很有前途。
3. Hydrogen storage function: Titanium-iron alloy has the property of hydrogen sorption, storing a large amount of hydrogen safely, and then releasing it in certain circumstances. Thus, it has a promising usage future in hydrogen separation, hydrogen purification, hydrogen storage, transportation and production of heat pump which fueled by hydrogen, storage battery and so forth. |
