Strength-Ductility Relationship in Solution Treated and Aged α+β Type Ti-4.5%Al-3%V-2%Fe-2%Mo Titanium Alloy
Strength-Ductility Relationship in Solution Treated and Aged α+β Type Ti-4.5%Al-3%V-2%Fe-2%Mo Titanium Alloy
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固溶时效α+β型Ti-4.5%Al-3%V-2%Fe-2%Mo钛合金的强塑关系
DOI：
10.2355/isijinternational.44.1911
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发表时间：
2004
影响因子：
1.8
通讯作者：
C. Ouchi
中科院分区：
文献类型：
--
作者：
Hideaki Fukai;Kuni;C. Ouchi
研究了Ti-4.5%Al-3%V-2%Fe-2%Mo SP-700合金的显微组织随固溶处理或时效条件的变化，并通过光滑和缺口试样的拉伸试验研究了显微组织对该合金强塑性平衡的影响。 α+β区域的固溶处理形成了由初生α相和相变β相组成的两相组织，并且后者的组织和硬度随冷却速率的变化而变化。水淬相变β的显微组织为α"相、无热ω相和残留β相，而空冷则在β基体中形成针状α相，且其宽度随着冷却速率的降低而变厚。与空冷时效合金相比，水淬时效合金表现出更好的强度-塑性平衡，这可能是由于应变过程中空洞形成的延迟。该合金时效后的强度可以通过混合定律进行分析，显微硬度和体积分数发现转变的β相主要控制强度。通过增加该合金的氧含量，改善了强度-延展性平衡，缺口拉伸强度随着时效硬化以及固溶处理后冷却速率的增加而增加，并在1 300 MPa左右出现拉伸强度的峰值。
The microstructural variation with solution treating or aging conditions in SP-700 alloy with Ti-4.5%Al-3%V-2%Fe-2%Mo was investigated, and the effect of the microstructure on strength-ductility balance of this alloy was studied by tensile testing using both the smooth and notched specimens. Solution treating in the α+β region formed a two-phase microstructure consisting of the primary a and transformed β phases, and the microstructure and hardness of the latter were widely varied by the cooling rate. The microstructures of the transformed β obtained by water quenching were α", athermal ω and retained β phases, while air cooling formed acicular a in β matrix and its width became thicker with reduction of cooling rate. Water-quenched and aged alloy exhibited better strength-ductility balance compared with air-cooled and aged one, which appeared to be due to retardation of void formation during straining. Strength after aging in this alloy could be analyzed by a law of mixture, and micro-hardness and the volume fraction of the transformed β phase were found primarily to control strength. Reduction of hardness difference between the primary a and transformed β phases by the increase of the oxygen content of this alloy improved strength-ductility balance. Notch tensile strength increased with strengthening due to age-hardening and also the increase of cooling rate after solution treating, and showed a peak value at tensile strength of around 1 300 MPa.