MechanicalbehaviorsofC/SiCcompositessubjectedtouniaxialcompression athightemperaturesandhighstrainrates
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摘要: 利用高温电子万能试验机和具有高温同步自组装功能的Hopkinson压杆对二维C/SiC复合材料 进行了应变率为10-4~103s-1,温度为293~1273K下的单轴压缩力学性能测试。实验结果表明:二维C/ SiC复合材料破坏时并未表现出典型的脆性破坏,而是在应力达到压缩强度时出现了显著的应变软化,在经 历了较大的变形后才最终破坏,同时材料还表现出良好的高温承载能力及一定的温度和应变率依赖性。随着 温度的升高,复合材料的压缩强度呈降低的趋势。与准静态下室温压缩时相比,材料在1273K 时的压缩强 度的降低程度不超过30%,但压缩强度对应变率的敏感性随着温度的升高而增大。由于高温下试样氧化,C/ SiC复合材料压缩强度对应变率的敏感性在温度为1073K时显著增大。Abstract: ByusinganelectronicuniversaltestingmachineandasplitHopkinsonpressurebardevice, aseriesofuniaxialcompressionexperimentswerecarriedouttoexplorethemechanicalbehaviorsofa 2DwovenC/SiCcompositeinthetemperaturerangefrom293to1273Kandthestrainraterange from10-4to103s-1.Theexperimentalresultsshowasfollows.Thecompositehasexcellenthigh temperaturemechanicalpropertiesinthetestedtemperaturerange.Thecompressivestrengthofthe compositedecreasesnomorethanthirtypercentat1273Kunderquasi-staticcompressionifcompared withthatatroomtemperature.Catastrophicbrittlefailureisnotobservedforthespecimenstestedat differentstrainrates.Withtheincreaseoftheexperimentaltemperature,thecompressivestrengthof the2DC/SiCcompositedecreases,butthedependenceofcompressivestrengthonstrainrateincreases. Atthetemperaturesabove1073K,thesensitivityfactorofcompressivestrengthonstrainrate increasesremarkably.Itisproposedthatthesharpincreaseinthedependenceofcompressivestrength onstrainrateisduetotheoxidationofthecomposites.
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Key words:
- solid mechanics /
- compressivestrength /
- uniaxialcompression /
- C/SiCcomposite /
- high temperature /
- highstrainrate
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