p）、亞微米級棒狀α相（αr）和次生α相（αs）組成。結(jié)果表明，具有多尺寸α相的合金具有較高的強(qiáng)度和極好的塑性。當(dāng)合金的極限抗拉伸強(qiáng)度為1125.4 MPa時，合金的斷后伸長率可以達(dá)到18.3%。建立了合金強(qiáng)度與α相之間的關(guān)系，即合金的強(qiáng)度與α相的寬度以及平均間距的?1/2次冪成線性關(guān)系，尺寸和相間距較小的αs相通過對位錯滑移的阻礙作用使合金的強(qiáng)度大大提高。透射電子顯微鏡觀察表明，在α/β界面上存在大量的位錯塞積，而且在拉伸變形之后的αp相內(nèi)發(fā)現(xiàn)了大量的形變孿晶。當(dāng)位錯滑移受到阻礙時，在應(yīng)力集中處萌發(fā)孿晶，而孿晶又可以啟動一些難以滑移的位錯，同時塑性應(yīng)變在αp、αr、αs相和β基體中均勻分布，使得合金的塑性有較大提升。;To study the relationship between the microstructure and tensile properties of the novel metastable β titanium alloy Ti-5.5Cr-5Al-4Mo-3Nb-2Zr, a heat treatment process of ABFCA (solid solution in α+β region with subsequent furnace cooling followed by aging treatment finally) was designed, by which α phases of different sizes can be precipitated in the β matrix. The results show that the microstructure obtained by this heat treatment process is composed of primary α (αp) phase, submicro rod-like α (αr) phase and secondary α (αs) phase. The alloy with multi-scale α phase has an excellent balance between strength and ductility. The elongation is about 18.3% at the ultimate tensile strength of 1125.4 MPa. The relationship between the strength of the alloy and the α phase was established. The strength of the alloy is proportional to the power of ?1/2 of the average spacing and width of α phase. The αs phase with a smaller size and phase spacing can greatly improve the strength of the alloy by hindering dislocation slip. The transmission electron microscope analysis shows that there is a large amount of dislocation accumulation at the α/β interfaces, and many deformation twins are found in the αp phase after tensile deformation. When the dislocation slip is hindered, twins occur at the stress concentration location, and twins can initiate some dislocations that are difficult to slip. Meanwhile, the plastic strain is distributed uniformly among the αp, αr, αs phases and β matrix, thereby enhancing the ductility of the alloy."/>