共查询到19条相似文献,搜索用时 156 毫秒
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高温低应力下AZ31镁合金的蠕变性能及蠕变机理 总被引:1,自引:0,他引:1
研究了AZ31镁合金在高温、低应力下的蠕变性能及蠕变机理.结果表明,AZ31镁合金的高温蠕变具有明显的三阶段蠕变特征;随着温度和应力的增加,稳态蠕变速率增加,稳态蠕变速率区域缩短.温度大于420℃、较低应力时,AZ31镁合金的蠕变为晶界扩散控制的COBLE蠕变;较高应力时,与位错攀移控制的WEETMAN蠕变机制相吻合.当温度为320~420℃时,AZ31镁合金的蠕变为滑移控制的位错蠕变.计算了由COBLE蠕变向WEETMAN蠕变转变的临界应力σcr,该应力与P-N力τp在数值上具有如下关系:σcr≈(2~3)τp 相似文献
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《机械工程材料》2016,(1)
利用4道次搅拌摩擦加工(FSP)工艺,分别将粒径为20nm的单斜晶ZrO_2(M-ZrO_2)颗粒和40nm的正方晶ZrO_2(T-ZrO_2)颗粒添加到AZ31镁合金中制备了ZrO_2颗粒增强镁基复合材料,研究了复合材料的显微组织与力学性能,并与无强化颗粒FSP镁合金的进行了对比。结果表明:M-ZrO_2颗粒和T-ZrO_2颗粒增强镁基复合材料的晶粒尺寸分别约为6μm和2μm;两种ZrO_2颗粒均弥散分布于复合材料中,且均未与基体反应生成新物相;ZrO_2颗粒可有效提高镁合金的硬度、屈服强度和抗拉强度,且T-ZrO_2颗粒的强化效果更好;无强化颗粒FSP镁合金与M-ZrO_2颗粒增强复合材料拉伸断口均具有混合断裂特征,前者的韧性断裂特征较明显,后者的脆性断裂特征较明显。 相似文献
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研究了铸造Al-Si颗粒氧化物复合材料中Cr2O3、Al2O3含量和粒度对材料磨损性能的影响;探讨了石墨对该复合材料磨损性能的影响。结果表明,含3%~4%(wt)颗粒氧化物的铝基复合材料呈现出较好磨损性能;而且在本试验条件下,含粒度较粗氧化物的铝基复合材料的磨损性能较好。作者认为,在较大载荷下,颗粒氧化物对配偶件(45钢)的磨损影响不大。 相似文献
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利用CETRUMT-2试验机及LKDM-2000轮廓摩擦磨损仪考察CuO颗粒填充PA1010复合材料的静态蠕变特性、松弛特性,利用Tribo Indenter测试系统考察复合材料的动态黏弹特性。结果表明:CuO颗粒填充后复合材料仍具备黏弹性质;复合材料的静态蠕变量、残余变形及损失正切tanδ均小于PA1010材料,且CuO颗粒含量越多,复合材料的黏弹性质越不显著。 相似文献
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RETRACTED ARTICLE: Wear Mechanism for In Situ TiC Particle Reinforced AZ91 Magnesium Matrix Composites 总被引:1,自引:0,他引:1
Junping Yao Wen Li Lei Zhang Fajun Wang Mingshan Xue Hongliu Jiang Jinshan Lu 《Tribology Letters》2010,38(3):253-257
TiC reinforced AZ91 magnesium matrix composites have been fabricated by a melt in situ reaction spray deposition. The microstructures
of spray-deposited alloys were studied by using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The dry sliding
wear behavior of the alloys was investigated by using a pin-on-disc machine under five loads, namely 10, 20, 30, 40, and 50 N.
The composites had much better wear-resistance than the matrix alloy. The wear behavior of the composites was dependent on
the TiC content in the microstructure and the applied load. The improvement in the wear resistance of the composites became
more prominent at larger normal load. At a lower load (10 N), with increasing TiC content, the wear rate of the composite
was decreased, and the dominant wear mechanism was an oxidative mechanism. At a higher loads (50 N), a spray-deposited AZ91/TiC
composites exhibited superior wear resistance to the AZ91 magnesium alloy, and the dominant wear mechanism was delamination. 相似文献
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研究了以AZ61镁合金为基体,添加不同含量的La、Ce、Nd、Gd稀土元素,生成的第二相尤其是稀土相Al11La3、Al4Ce、Al2Nd、Al2Gd对AZ61镁合金力学性能的影响。AZ61+2%Gd合金中的第二相大部分呈球粒状,其有利于提高合金的综合力学性能。 相似文献
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Li Zhang Qudong Wang Guoping Liu Wei Guo Bing Ye Wenzhen Li Haiyan Jiang Wenjiang Ding 《Tribology Letters》2018,66(2):71
Reciprocating wear tests were conducted to assess the wear resistance of CNT-reinforced AZ91D composites prepared by cyclic extrusion and compression (CEC). Effects of CEC, CNTs, and wear parameters on the tribological behavior of the composites were discussed. Results show that the matrix grain of the 0.5 wt% CNTs/AZ91D composites is largely refined from ~?112 µm to 126.6 nm after eight passes of CEC. Accordingly, the hardness of the composites is increased by more than 82.0%. The wear rate of the CNTs/AZ91D composites decreases with the implement of CEC and the addition of CNTs. The lubrication effect of CNTs diminishes after CEC. Besides the reinforcing effect, the incorporated CNTs help to liberate the friction heat of the CNTs/AZ91D composites and reduce the welding of the wear debris due to their extraordinary thermal conductivity. 相似文献
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Copper matrix composites reinforced with MgO, Al2O3, SiO2, and SiC nanoparticles were fabricated by powder metallurgy. The tribological properties of the composites were examined using a self-made pin-on-disk electrical wear tester. Thermal expansion properties of the prepared composites were evaluated by their coefficient of thermal expansion from 50 to 500°C. The effect of the thermal expansion characteristics of reinforcements on the electrical wear performance of the composites was also studied. The results showed that the wear rates of MgO/Cu and Al2O3/Cu composites were lower than those of SiC/Cu and SiO2/Cu composites, which were also consistent with the difference between the coefficient of thermal expansion of the copper matrix and reinforcements. The relationship was analyzed by calculation of the thermal stress at the copper matrix–reinforcement interface in the electrical sliding process. Microstructural observation revealed that the wear mechanisms of the copper matrix composites were mainly adhesive wear and plastic deformation accompanied by a small amount of arc damage. 相似文献
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材料增强用碳化硼颗粒表面改性涂层的研究 总被引:3,自引:0,他引:3
介绍用一种蒸 镀的方法在碳化硼颗粒(B4Cp)表面涂覆一层含钛金属的涂层,使得金属基复合材料的B4Cp-Me体系中的界面结合强度得到改善。 通过X射线衍射、差热分析和热重分析等分析了涂的结构变化,用粉末冶金法制备了B4C颗粒增强Cu、Al基复合材料,通过磨损实验评价了界面结合强度。试验结果表明,经涂覆后B4Cp表面的结构组成由内向外依次为B4C、TiB2、TiN。差热分析也证实了涂覆后的B4Cp表面产生新的物相,热重分析表明经涂覆后的B4Cp的热稳定性较末涂覆的高。磨损实验表明,使用经过涂覆的颗粒所制备的复合材料具有更高的耐磨性。 相似文献
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Fretting wear behavior of AZ91D and AM60B magnesium alloys 总被引:2,自引:0,他引:2
The fretting wear behavior of the AZ91D and AM60B magnesium alloys are investigated using a reciprocating fretting wear machine under dry conditions with different numbers of cycles, different normal loads, slip amplitudes and frequencies. The worn surfaces and wear debris were examined using scanning electron microscopy and optical microscopy in order to understand the predominant wear mechanisms of two magnesium alloys. The results indicate that the AZ91D alloy displays a lower friction coefficient and lower wear quantity than the AM60B alloy. The AZ91D shows a higher capability than AM60B in resisting crack nucleation and propagation. Both AZ91D and AM60B show similar friction and wear characteristics. The wear quantity increases with increasing normal load, but decreases with increasing frequency. The friction coefficient also decreases as the normal load is increased. Fretting frequency had little effect on the friction coefficient. In a long term, the fatigue wear and abrasive wear were the predominant wear mechanisms for AM60B and delamination wear, adhesive wear and abrasive wear for AZ91D. 相似文献