B掺杂Ti-V-Al轻质高强记忆合金组织结构与应变恢复特性
发布时间：2019-07-02 18:41
【摘要】：本文根据Ti-V-Al合金屈服强度低,难以满足高性能连接要求的问题提出了B掺杂的合金化方法,提高合金的强度。采用扫描电镜,X射线衍射仪,金相显微镜,扫描示差量热分析仪,室温拉伸仪,透射电镜观察等设备系统研究了Ti-V-Al-B形状记忆合金的组织结构与应变恢复特性,分析了B含量及热机械处理对Ti-V-Al合金组织结构,马氏体相变,力学性能,形状记忆效应的影响规律和机制。研究表明,固溶态Ti-V-Al-B合金的室温组织为正交结构的α"马氏体相,B的加入并未改变合金的室温组织。650℃退火时,合金基体由α"和少量α相组成,随着退火温度的升高,合金的中的α相体积逐渐增大,数量逐渐减少,分布变得不均匀。当B元素含量低于0.01at%时,合金中无第二相生成,随着B元素的增加,合金中逐渐生成斜方结构的纤维状TiB相,并由弥散分布于基体中间变为趋向于延晶界分布。B的掺杂有效减小了合金的晶粒尺寸,固溶态合金晶粒由Ti-13V-3Al的284μm下降到了(Ti-13V-3Al)99。9B0.1的75μm左右。随着B的添加(Ti-13V-3Al)_(100-x)B_x合金的逆相变温度先下降后上升,对(Ti-13V-3Al)_(99.9)B_(0.1)合金进行650℃退火,合金无法观察到逆相变峰,随着退火温度的升高,逆相变峰出现且逆相变温度逐渐趋近于固溶态(Ti-13V-3Al)_(99.9)B_(0.1)合金。B的加入及热机械处理都有效提升了合金的相变循环稳定性。经五次热循环后,(Ti-13V-3Al)_(99.9)B_(0.1)合金的逆相变温度下降了65.4℃,热机械处理后的(Ti-13V-3Al)_(99.9)B_(0.1)合金逆相变温度仅下降了26.89℃,随着B含量的增加固溶态Ti-V-Al-B合金的屈服强度,抗拉强度和延伸率呈现先上升后下降的趋势,当B含量为0.1at%时,合金的屈服强度合抗拉强度达到711MPa和987MPa,比未掺杂B元素的Ti-13V-3Al合金高了51.9%和39%。随着退火温度的升高,合金的屈服强度逐渐下降,延伸率逐渐升高。随着固溶时间的增长,合金的屈服强度及抗拉强度逐渐增加,延伸率逐渐下降。B元素的加入有效改善了合金的形状记忆效应,合金的可恢复应变随B含量的增加上升后下降,当B含量为1at%时,完全可恢复应变达到4%,预应变为6%时,合金的可恢复应变达到5.01%。随着退火温度的增加,合金的记忆效应逐渐下降,700℃时记忆效应达到最好。
[Abstract]:In this paper, according to the problem that the yield strength of Ti-V-Al alloy is low and it is difficult to meet the requirements of high performance bonding, a B-doping alloy method is proposed to improve the strength of the alloy. The microstructure and strain recovery characteristics of Ti-V-Al-B shape memory alloy were systematically studied by means of scanning electron microscope, X-ray diffractometer, metallographic microscope, scanning differential thermal analyzer, room temperature extensor and transmission electron microscope. The effects of B content and thermomechanical treatment on the microstructure, maraging, mechanical properties and shape memory effect of Ti-V-Al alloy were analyzed. The results show that the microstructure of solid solution Ti-V-Al-B alloy at room temperature is 伪 "marsite phase with orthogonal structure at room temperature, and the addition of B does not change the room temperature microstructure of the alloy. When annealed at 650 鈩，
本文编号：2509144
[Abstract]:In this paper, according to the problem that the yield strength of Ti-V-Al alloy is low and it is difficult to meet the requirements of high performance bonding, a B-doping alloy method is proposed to improve the strength of the alloy. The microstructure and strain recovery characteristics of Ti-V-Al-B shape memory alloy were systematically studied by means of scanning electron microscope, X-ray diffractometer, metallographic microscope, scanning differential thermal analyzer, room temperature extensor and transmission electron microscope. The effects of B content and thermomechanical treatment on the microstructure, maraging, mechanical properties and shape memory effect of Ti-V-Al alloy were analyzed. The results show that the microstructure of solid solution Ti-V-Al-B alloy at room temperature is 伪 "marsite phase with orthogonal structure at room temperature, and the addition of B does not change the room temperature microstructure of the alloy. When annealed at 650 鈩，
本文编号：2509144
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