喷雾共沉积颗粒增强锌基复合材料的高频内耗

采用喷雾共沉积技术在ZA27合金中添加50mg．g-1Si制备了体积分数为10％的石墨、SiC增强锌基复合材料。用声频内耗仪对挤压前后材料的高频内耗行为进行了测量。结果发现,30℃时石墨、SiC增强复合材料的阻尼能力较常规铸造ZA27合金分别提高2．90和2.38倍;挤压后两种复合材料内耗值相当接近（约为常规铸造ZA27合金的4．3倍）。在微观组织形貌分析基础上探讨了石墨、SiC颗粒对复合材料内耗机制的影响。     

热处理和锰含量对CuZnAl合金微观组织结构和宏观性能的影响

采用万能试验机、金相显微镜、扫描电子显微镜以及动态热机械分析仪,研究了时效时间以及Mn元素对CuZnAl合金微观组织结构、力学及阻尼性能的影响。结果表明:Mn元素可以改善材料微观组织结构,提高合金的阻尼性能和拉伸强度;微观组织结构中的针状马氏体和块状马氏体随时效热处理时间的增长发生显著变化,并由此影响材料的阻尼性能;阻尼性能与针状马氏体的长度和密度呈正相关,而与块状马氏体的数量呈负相关,但Mn含量过高时,例如达到10%,出现粗大的块状组织,合金力学性能会有明显下降。     

喷雾共沉积法制备功能结构材料

概述了喷雾共沉积工艺的典型特点，指出喷雾共沉积工艺在高阻尼减振材料，耐磨减摩材料，高强度高导电材料制备方面具有广阔的前景。     

高强高阻尼Mg-Zr系合金的研究(Ⅱ)——热挤压及退火对Mg-Zr-(Ca/Y)合金组织和性能的影响

研究了三种Mg-Zr系阻尼合金（Mg-0．6Zr．Mg-0．6Zr-0．3Ca，Mg-0．6Zr0．3Ca-0．1Y）住热挤压及退火后组织和性能的变化。结果表明：合金在热挤压过程中晶粒明显细化．使力学性能得到提高。三种合金在铸态下，其阻尼性能随应变振幅的增加而不断提高；经过热挤压后，阻尼性能明显下降，且几乎与应变振幅无关；挤压后的退火处理又使合金阻尼性能有所增大．但与铸态时仍存在一定差距。在各处理状态下，Mg-0．6Zr-0．3Ca和Mg-0．6Zr-0．3Ca-0．1Y合金的力学性能明显高于Mg-0．6Zr合金，而阻尼性能在铸态下与Mg-0．6Zr合金相差不大，但经热挤压和退火后有较大差距。三种合金阻尼性能随处理状态的变化可用Granato-Liicke值错模型解释。     

磷元素对Fe-Mn阻尼合金性能影响研究

Fe-Mn基阻尼合金是近些年来发现的一种新型金属阻尼材料。以Fe-Mn基阻尼合金为研究对象,对经不同固溶温度（800、900、1 000℃）处理后的Fe-Mn、Fe-Mn-P阻尼合金的力学性能、耐蚀性能、阻尼性能进行了测试,利用EBSD进行了显微组织结构表征。结果表明：磷元素添加提高了阻尼合金的屈服强度,有利于提高合金的耐腐蚀性能,但极大地恶化了阻尼合金的低温韧性,降低了阻尼合金的阻尼性能。在800℃固溶状态下,Fe-Mn-P合金阻尼性能最佳,随着固溶温度的升高,Fe-Mn-P阻尼合金强度降低,阻尼性能降低;ε/ε和ε/γ界面密度是影响FeMn-P阻尼合金阻尼性能的重要因素。     

喷射成形工艺参数及热挤压制度对8009耐热铝合金的组织及性能的影响

采用喷射成形方法制备了A1-8．5Fe-1．4v-1．7Si(8009)耐热铝合金，研究了喷射成形工艺参数及沉积坯件的热挤压工艺对材料的微观组织及性能的影响。结果表明：喷射成形工艺能够有效地抑制8009合金中粗大的富铁相的析出，获得均匀细小的组织；当喷射成形工艺参数选择适当时，沉积坯件具有良好的成形性与致密度，在随后的热挤压过程中，通过较低的挤压比即可使材料达到全致密。合金经过热挤压后，在室温及高温下均具有良好的力学性能。     

高强高阻尼Mg-Zr系合金的研究（Ⅰ）——Ca／Y变质处理Mg-0．6Zr合金阻尼行为的研究

采用动态机械热分析（DMA）技术研究了Ca／Y变质处理对Mg-0．6Zr合金阻尼行为的影响，分析了合金随应变振幅和温度阻尼变化的机制。结果表明，添加0．3％Ca和0．3％Ca＋0．1％Y（质量分数，下同）变质处理后的细晶强化和固溶强化作用提高了合金的拉伸强度和延伸率，同时由于Ca／Y元素的加入及晶界数量增多对位错运动的进一步阻碍作用降低了合金的应变振幅效应，从而降低了其阻尼性能；研究还发现Mg-0．6Zr合金在温度为75℃处出现一个明显的阻尼峰，而添加0．3％Ca＋0．1％Y变质处理后，并未出现阻尼峰。分析认为，试验合金的阻尼机制可按G-L位错钉扎模型和晶界面软化及粘性滑动机制解释。     

喷雾造粒钼粉制作Mo-Cu合金微观形貌及性能分析

试验分析了采用喷雾造粒钼粉熔渗法制作Mo-Cu合金的微观形貌及性能。结果表明:熔渗后多孔钼骨架被Cu相充满但存在微量球状孔隙,Cu相形成了网络状的微观形态并存在富集区;采用喷雾造粒钼粉制作的Mo-Cu合金相对密度、布氏硬度、导热率和线膨胀系数等性能满足客户使用要求。     

Ni和Nb元素对Fe-Cr-Mo合金力学和阻尼性能的影响

采用光学显微镜、扫描电镜、透射电镜、弯曲共振试验机和万能材料试验机等分析了复合添加质量分数0.8%Ni元素和0.1%Nb元素的Fe-Cr-Mo合金组织和析出相的大小、形态,研究了Ni和Nb元素的添加对FeCr-Mo合金力学性能和阻尼性能的影响。结果表明,Ni和Nb元素的加入不但使合金晶粒显著细化,而且有效抑制了富Cr析出物的析出,使析出物明显细化且分布弥散。晶粒和析出物的细化同时提高了合金的强度和塑韧性,尤其是显著地提高了材料的塑性。1 000和1 100℃退火后,Ni和Nb元素的加入将提高减振合金的矫顽力,降低磁致伸缩系数,使减振合金的阻尼性能降低。900℃退火后,Ni和Nb元素的添加虽然提高了合金的矫顽力,但由于Mo元素的回溶使磁致伸缩系数增大,阻尼性能获得提高。     

Ni和Nb元素对Fe-Cr-Mo合金力学和阻尼性能的影响

摘要：采用光学显微镜、扫描电镜、透射电镜、弯曲共振试验机和万能材料试验机等分析了复合添加质量分数0.8%Ni元素和0.1%Nb元素的Fe-Cr-Mo合金组织和析出相的大小、形态,研究了Ni和Nb元素的添加对Fe-Cr-Mo合金力学性能和阻尼性能的影响。结果表明,Ni和Nb元素的加入不但使合金晶粒显著细化,而且有效抑制了富Cr析出物的析出,使析出物明显细化且分布弥散。晶粒和析出物的细化同时提高了合金的强度和塑韧性,尤其是显著地提高了材料的塑性。1000和1100℃退火后,Ni和Nb元素的加入将提高减振合金的矫顽力,降低磁致伸缩系数,使减振合金的阻尼性能降低。900℃退火后,Ni和Nb元素的添加虽然提高了合金的矫顽力,但由于Mo元素的回溶使磁致伸缩系数增大,阻尼性能获得提高。     

Influence of RE Content on Damping Capacity of Alloy ZA27

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ZA27铸造合金的凝固特性

研究了ZA27铸造合金中的常见微量元素以及铸件厚度、浇注温度、变质处理对ZA27合金凝固特性的影响。实验结果表明,铸件厚度是影响ZA27合金凝固特性的最主要因素,适量的Ti可以改善ZA27合金的凝固特性,浇注温度及变质处理对ZA27合金的凝固特性也有不同程度的影响。根据实验结果,推荐了较佳工艺参数。     

高韧性锌基合金的成分、性能及耐磨性

在ZA27合金的基础上,研究了Al、Cu及微量元素B、Ti对锌基合金力学性能的影响,确定了高强韧锌基耐磨合金-ZA30的成分为：w（Al）=29％-31％,w（Cu）=2．0％-2．5％,w（Mg）=0．01％-0．02％,Zn：余量,B、Ti微量．进行了与ZA27在46#工业齿轮油润滑条件下的耐磨性能的对比试验,并对合金耐磨机理及各元素对合金性能影响的机理进行了探讨．研究结果表明：与ZA27相比,ZA30在强度略有提高的基础上,延伸率从3％-6％提高到12．1％-17．3％：ZA30的耐磨性优于ZA27．     

Fe元素对ZA27合金显微组织和力学性能的影响

在ZA27合金中添加0.5%~2%的Fe元素,利用金相、扫描电镜(SEM)、能谱分析(EDS)、X射线扫描(XRD)、拉伸实验等测试手段,研究Fe含量对ZA27合金显微组织和力学性能的影响。结果表明:不同Fe含量的ZA27合金基体组织均由富铝的α相和富锌的η相组成。Fe元素以FeAl3金属间化合物的形式分布于基体中。随Fe含量增加,FeAl3的含量增多、尺寸增大。FeAl3能阻碍晶界迁移,起到细化枝晶的作用。研究还发现,室温下,随Fe含量增加,ZA27的强度和伸长率均降低;150℃高温下,Fe含量为1.5%左右的ZA27合金抗拉强度达192.75MPa,比未加Fe元素的ZA27合金提高约54.4%,伸长率达15.65%,从而获得兼具高强度和高塑性的高温ZA27合金。     

Effects of macroscopic defects on the damping behavior of aluminum and Zn-27 Pct Al alloy

A study was carried out on the influence of macroscopic defects on the damping behavior of commercially pure Al and Zn-27 pct Al alloy. The macroscopic defects, pores, and graphite particulates with a size of 0.001±0.0005 m and volume fractions ranging from 19 to 94 pct were introduced into the structures by infiltration technology. It has been shown that pores or graphite particulates can improve the damping capacity of commercially pure Al, due to the interaction between macro- and microdefects. Pores, however, show no detectable effects on the damping behavior of high damping Zn-27 pct Al alloy. Similarly, graphite particulates have little effect on the damping capacity of Zn-27 pct Al alloy at low temperatures and, on the contrary, make the transformation peak value of internal friction decrease. It is considered that graphite particulate may repress the eutectoid transformation process of Zn-27 pct Al alloy.     

Enhancing the Damping Behavior of Dilute Zn-0.3Al Alloy by Equal Channel Angular Pressing

The effect of grain size on the damping capacity of a dilute Zn-0.3Al alloy was investigated. It was found that there was a critical strain value (≈1 × 10⁻⁴) below and above which damping of Zn-0.3Al showed dynamic and static/dynamic hysteresis behavior, respectively. In the dynamic hysteresis region, damping resulted from viscous sliding of phase/grain boundaries, and decreasing grain size increased the damping capacity. While the quenched sample with 100 to 250 µm grain size showed very limited damping capacity with a loss factor tanδ of less than 0.007, decreasing grain size down to 2 µm by equal channel angular pressing (ECAP) increased tanδ to 0.100 in this region. Dynamic recrystallization due to microplasticity at the sample surface was proposed as the damping mechanism for the first time in the region where the alloy showed the combined aspects of dynamic and static hysteresis damping. In this region, tanδ increased with increasing strain amplitude, and ECAPed sample showed a tanδ value of 0.256 at a strain amplitude of 2 × 10⁻³, the highest recorded so far in the damping capacity-related studies on ZA alloys.

     

Modification Mechanism of Rare Earth Elements in ZA27 Casting Alloys

The model of the liquid-phase ZA27 alloys was set up by molecular dynamics theory. The atomic structure of phase, RE-compounds, and the phase-liquid interface in ZA27 alloys were constructed by computer programming. Electronic structures of phase with rare earth elements dissolved and of phase-liquid interfaces with rare earth elements enrichment in ZA27 casting alloys were investigated by using the Recursion method. The ESE energy of RE elements and the structure energy of RE-compounds, phase, and the liquid-phase ZA27 alloys were calculated. The results show that rare earth elements are more stable to be in the phase interface than in phase, which explains the fact of very small solid solubility of rare earth elements in phase, and the enrichment in the solid-liquid growth front. This makes dendrite melt and break down, dissociate and propagate. RE-compounds can act as heterogeneous nuclei for phase, leading to phase refinement. All above elucidates the modification mechanism of rare earth elements in zinc-aluminum casting alloys, at electronic level.     

Influence of La and RE on the Underside Shrinkage of ZA27 Alloy

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Damping behavior of Al-Li-SiC<Subscript>p</Subscript> composites processed by stir casting technique

Damping characteristics of 8090 Al alloy and its composites reinforced with 8, 12, and 18 vol pct SiC particles were investigated using a dynamic mechanical analyzer (DMA). Tests were done at different frequencies over a temperature range of 27 °C to 300 °C. Composites show higher damping capacity than the unreinforced alloy. Damping capacity is found to increase with decreasing frequency. An equation relating damping capacity with frequency has been proposed. The damping data are analyzed in the light of matrix microstructure and different operative mechanisms.