CuZnAl合金在拘束训练条件下双程记忆性能的研究

本文就Cu-25.71Zn-4.18Al合金在约束训练条件下的双程记忆性能和机理作了一些研究。结果表明:对Cu-Zn-Al合金采用拘束训练后可获得较好的双程记忆性能,双程恢复角可达70°,训练后的合金做成的元件在80℃作长时间停留双程记忆,性能稳定,热循环疲劳寿命到达15500次。拘束训练所获得的双程记忆主要与残余菱形马氏体组织有关。     

对Fe-Mn合金阻尼性能和耐腐蚀性能的影响

为了提高Fe-Mn阻尼合金的抗腐蚀性能,在Fe-Mn二元合金中加入一定量的Cr元素,采用倒扭摆法测试Fe-19Mn,Fe-17Mn-2Cr和Fe-16Mn-6Cr三种合金的阻尼性能,采用失重法测试合金在3%NaC l溶液中的耐腐蚀性能,采用OLYMPUS显微镜分析合金的微观组织。结果表明,在0.5×10-4~5.5×10-4的扭转应变振幅范围内,三种合金的阻尼性能随应变振幅的变化趋势一致,呈现近似线形增加;Fe-19Mn合金阻尼性能高于Fe-17Mn-2Cr和Fe-16Mn-6Cr,而后两种合金阻尼性能相当;同时Cr的加入提高了Fe-Mn合金的耐腐蚀能力。     

杂质元素对FeMn合金阻尼性能的影响

为了解材料纯洁度对FeMn合金阻尼性能的影响,采用倒扭摆测试两种杂质含量不同的FeMn合金的阻尼性能,XRD测试合金的层错几率和ε马氏体体积分数,采用OLYMPUS金相显微镜观察合金的微观组织。结果表明,两种合金的阻尼性能都随应变振幅的增加而呈线性增加;杂质含量对FeMn合金阻尼性能影响较大,杂质含量为0.722％的2#合金与杂质含量为0.235%的1#合金相比,在应变振幅为4.5×10-4时其对数衰减率降低了近20％。这是由于杂质元素含量越多,Shockley不全位错上的弱钉扎点就越多,脱钉运动的阻碍就越大,合金阻尼性能也就越低。     

Cr对Fe-Mn合金阻尼性能和耐腐蚀性能的影响

为了提高Fe-Mn阻尼合金的抗腐蚀性能,在Fe-Mn二元合金中加入一定量的Cr元素,采用倒扭摆法测试Fe-19Mn,Fe-17Mn-2Cr和Fe-16Mn-6Cr三种合金的阻尼性能,采用失重法测试合金在3%NaCl溶液中的耐腐蚀性能,采用OLYMPUS显微镜分析合金的微观组织.结果表明,在0.5×10-4～5.5×10-4的扭转应变振幅范围内,三种合金的阻尼性能随应变振幅的变化趋势一致,呈现近似线形增加;Fe-19Mn合金阻尼性能高于Fe-17Mn-2Cr和Fe-16Mn-6Cr,而后两种合金阻尼性能相当;同时Cr的加入提高了Fe-Mn合金的耐腐蚀能力.     

合金元素对Fe-Mn合金层错几率和阻尼性能的影响

对Fe-19Mn、Fe-17Mn-2Cr和Fe-19Mn-1.5Si这3种合金的层错几率和阻尼性能进行研究。采用倒扭摆测试合金的阻尼性能,XRD测试合金的层错几率和ε马氏体体积分数。结果表明,3种合金的阻尼性能都随着应变振幅的增加呈现近似线形增加,这可以通过Shockley不全位错的脱钉运动来解释;Si元素增加了Fe-Mn合金的层错几率和Shockley不全位错数量,但是由于原子半径的差异,其引起的晶格畸变很大,产生的空位等缺陷钉扎了Shockley不全位错的运动,因此显著降低了Fe-Mn合金的阻尼性能;     

训练及热循环对CuZnAl合金马氏体形态的影响

本文研究了ＣｕＺｎＡｌ形状记忆合金在训练后以及热循环后热弹性马氏体的形态；分析了马氏体形态对该合金的双程记忆效应的影响。     

提拉法制备马氏体NiAl合金的研究

要用提拉法无污染磁悬浮冷坩埚技术生长出NiAl合金晶体。通过XRD、EPMA、SEM对其进行了物相、成分及显微结构分析、结果表明,从高温急冷下来的Ni-34at%Al合金具有板条状马氏体结构,且在晶界处分布着枝状的Ni3Al。     

CuZnAl（Mn）合金双程记忆性能的衰减特性

本文探讨了CuZnAl,CuZnAlMn合金的弹簧试样在相变热循环过程中双程记忆性能的变化规律,表明引起铜基形状记忆合金双程记忆性能衰减的主要因素是由于位错增殖;在有外加应力条件下热循环时,还要考虑应力诱发马氏体对记忆性能的贡献。少量Mn的加入使CuZnAl合金在热循环过程中位错增殖加速,同时使应力诱发马氏体容易产生,结果导致在有外加应力条件下热循环时Mn能缓和记忆性能的衰减。     

合金元素及热处理方式对CuZnAl系合金形状记忆恢复力的影响

本文研究了CuZnAl系合金马氏体稳定化去除后,合金元素及热处理方式对形状记忆恢复力的影响。结果表明,合金形状记忆恢复力的大小与其屈服强度有关,改变合金成份或变更热处理方式使合金屈服强度升高,形状记忆恢复力将相应增大,有利于提高合金的恢复性能,合金处于拘束状态时将使恢复温区明显增大,但对恢复开始点As基本没有影响。     

Al-Zn阻尼合金的研究

本文研究了Al-Zn合金的成分、组织以及使用温度对阻尼性能的影响.研究中发现合金的成分、热处理方式对组织具有很大的影响,当合金呈粒状组织时,具有较好的阻尼性能.同时,Al-Zn合金具有较高的高温阻尼性能,并在245℃时达到阻尼的最大值,文中提出了解释该现象的模型.     

Damping performance of Cu-Zn-Al shape memory alloys in engineering structures

The stress strain curves of two CuZnAI shape memory alloys which have the martensltic transformation temperatures of 50℃ and-10℃ respectively, were measured by using electronic material tester after treated by different heat-treatment conditions. The results show that the area enclosed by hysteresis loop of the CuZnAI shape memory alloy in martensltic state is much larger than that of the alloy in austenltic state with super-elasticity at room temperature. Therefore, the former has better vibration attenuation effect. After being oil-quenched, waterquenched, and step-quenched, the CuZnAI alloy takes on more stable shape memory effect, better super-plasticlty and superelasticity (pseudoelasticity). A CuZnAI shape memory alloy damper was designed, produced and installedto a 2-layer frame structure. In addition, the vibration experiments were made by dynamic data collecting analysis meter. The velocity of vibration attenuation of frame structure with CuZnAI shape memory alloy damper is much faster than that without it. And with the help of CuZnAI shape memory alloy damper, the attenuation period reduces to 1/10 of the original.     

A growth manner of butterfly martensite

The growth of butterfly martensite in an Fe-Ni-V-C alloy was investigated using an optical microscope and transmission electron microscope through observing its morphology. The present butterfly martensite is dislocation-type, with a few fine twins. One wing of a butterfly martensite is layered more heavily than the other and the concave part is layered more obviously than other regions. Most butterfly martensites have a lath plate outside of and next to one wing. The outside martensite plates grow first, and then two wings of butterfly martensite. The smooth parts of a butterfly martensite grow earlier than the layered regions. A wing of a butterfly martensite grows like a group of lath martensites.     

CuZnAl形状记忆合金回复应力的研究

CuZnAl形状记忆合金如果作为管接头和一些驱动元件使用时,主要利用的是其形状回复时受阻（约束条件）进而产生的回复应力.对Cu-26.87%Zn-3.85%Al（wt%）合金在约束条件下,加热和冷却过程中回复应力的变化和不同的回复加热温度对回复应力的影响进行了研究.实验结果表明,约束条件下,实验合金的回复应力在加热过程中逐渐升高,在210～250 ℃范围内达到最大值242 MPa,随后逐渐降低;冷却过程中回复应力短暂下降后,逐步升高,在130～150 ℃范围内达到最大值204 MPa,随后大幅度下降;实验合金加热温度不能高于其再结晶温度,否则其回复应力会大幅度松弛;为了在加热和冷却过程中获得的回复应力最大,实验合金的最佳回复加热温度为200 ℃左右.     

Cu-Al-Be-B合金马氏体形貌和亚结构

用光学显微镜和透射电镜分析研究了Cu-11.42Al-0.35Be-0.18B(质量分数,%)形状记忆合金的马氏体的组织形态及亚结构.结果表明,Cu-11.42Al-0.35Be-0.18B(质量分数,%)合金的马氏体的形貌组态较复杂,主要有平行状、矛头状和竹节状,亚结构主要为位错、层错.矛头状自协作形态的马氏体的变体呈竹节状.用XRD分析了晶界析出相α相,其化学式为AlCu4.     

Effect of Si on austenite stabilization,martensite morphology,and magnetic properties in Fe-26%Ni-x%Si alloys

The effect of Si on the austenite stabilization, martensite morphology, and magnetic properties in Fe-26%Ni-x%Si (x=3.5, 5, and 6) alloys have been studied by means of transmission electron microscopy (TEM) and M?ssbauer spectroscopy techniques. TEM observations reveal that the martensite morphology is closely dependent on the Si content. The volume fraction changes of martensite and austenite phases, the hyperfine magnetic field, and isomer shift values have been determined by Mssbauer spectroscopy. The M...     

CuZnAl合金氩弧焊焊接性能研究

采用与母材同质的焊丝,研究了铜合金CuZnAI氩弧焊的焊接性能,并利用金相显微镜、扫描电镜、电子探针对接头进行了金相检验、力学试验和成分分析。结果表明,接头强度与母材接近,断口呈浅韧窝状,塑性较好;但在焊接时,由于Zn,AI挥发强烈,焊缝成分发生变化,对其形状记忆效应略有影响。     

Effect of HIPing time on the properties of TiAl alloys

The compacted TiAl alloys were prepared and the effects of HIPing time on their properties were studied. At 1100 ℃, 80 Mpa, the density of TiAl alloy reached up to 3.46 g/cm3 after 10 min HIPing. The densities of TiAl alloys did not significantly increase with the time increasing from 10 min to 70 min. Under the experimental conditions, the TiAl alloys obtained is an unstable state alloy, and the effect of HIPing time on the TiAl phase is not significant. The micro-cracks appear in inner of TiAl alloy with the HIPing time increase. At 1380 ℃, after one hour heat treatment, the micro-cracks disappear and the phase changes into stable state and its microstructure changs into lamella.