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利用弯曲应力松弛方法研究了魏氏组织和等轴组织BT20钛合金的应力松弛行为和应力松弛过程中的塑性应变速率和应力的关系。研究表明,在200℃应力松弛的时候,BT20合金等轴组织具有较好的抗松弛性能;在400℃和600℃时BT20合金魏氏组织具有较好的抗松弛性能。 相似文献
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研究了形变热处理对TA15钛合金组织与力学性能的影响。在α+β两相进行形变热处理使组织中的条状初生α相碎化。对水冷的试样进行930℃/1h/空冷+915℃/1h/空冷+530℃/6h/空冷的处理,抗拉强度明显提高,组织中的条状初生α相发生球化。在β相进行形变热处理使强度略有降低,魏氏组织中的α层片增厚。 相似文献
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C/C复合材料Mo-Si-N抗氧化涂层的制备 总被引:8,自引:0,他引:8
在C/C复合材料表面采用熔浆法制备Mo—Si系涂层的烧结过程中通入氮气,开发了Si3N4.MoSi2/Si—SiC(Mo-Si-N系)多层抗氧化涂层,并初步考察了涂层的抗氧化性能。结果表明,多层涂层的致密性主要受制于起始氮化温度。只有在Si熔点以上通入氮气,才能获得致密无缺陷的涂层。多层涂层的底层为SiC,外层为Si3N4,中间层为MoSi2/Si。这种多层涂层的抗氧化性能与涂层中MoSi2的含量有关;MoSi2含量为30%(体积分数,下同)和40%时,与真空中合成的Mo-Si涂层相比,高温抗氧化性能显著改善,抗氧化温度提高到1400℃~1450℃。 相似文献
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The spinodal decomposition in Fe-Mo alloys is studied by microscopic phase field method based on atomic scale.The results show that critical temperature of spinodal decomposition increases with the increment of Mo content,up to a maximum value of 1340 K at the Mo content of 50%.The spinodal decomposition shows a maximum rate at the Mo content of 50% for different Fe-Mo alloys.Comparing with the interconnected microstructure without considering elastic strain energy,the microstructure arrayed alternatively along the elastic soft direction of [01] and [10] is obtained under the effects of elastic strain energy,which will changes into a special "macrolattice" structure during subsequent coarsening stages.The coarsening of microstructure is restrained by elastic interaction generated by atomic-size difference,and a larger atomic-size difference induces a stronger restraining effect. 相似文献
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HA-Ti生物功能梯度材料微观组织及热应力缓和特性 总被引:9,自引:0,他引:9
本文用粉末冶金法制备了HA-Ti系生物FGM,并测定了HA-Ti复合体材料的弹性模量和热膨胀系数.应用经典叠层板理论和热弹性力学理论分析了HA-Ti系NFGN双层板和HA-Ti系FGM的制备残余热应力和热应变.结果表明,HA-Ti系生物FGM呈现出宏观不均匀性与微观连续性的组织特征.HA-Ti系复合体材料的弹性模量在Ti-HA80达到谷值,并受到气孔率的影响.其热膨胀系数随着HA含量和测试温度的升高而增大.残余热应力和残余热应变强烈依赖于组成分布,FGM由于组成梯度化减小了成分变化幅度,其最大残余拉应力只有HA/Ti直接叠合体(NFGM)的1/3,具有显著缓和热应力的功能. 相似文献
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The multi-component A1CrCuFeMnTi high entropy alloy was prepared using a vacuum arc melting process. Serial annealing processes were subsequently performed at 590 ℃, 750 ℃, 955 ℃ and 1 100 ℃ respectively with a holding time of 4 h at each temperature. The effects of annealing on microstructure, mechanical and electrical properties of as-cast alloy were investigated by using differential thermal analysis (DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The experimental results show that two C14 hexagonal structures remain unchanged after annealing the as-cast A1CrCuFeMnTi alloy specimens being heated to 1 100℃. Both annealed and as-cast microstructures show typical cast-dendrite morphology and similar elemental segregation. The hardness of alloys declines as the annealing temperature increases while the strength of as-cast alloy improves obviously by the annealing treatment. The electrical conductivities of annealed and as-cast alloys are influenced by the distribution of interdendrite re~ions which is rich in Cu element. 相似文献
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等离子喷涂ZrO2/NiCoCrAlY梯度涂层中ZrO2组元的显微结构特征 总被引:3,自引:0,他引:3
Zro2/NiCoCrAlY梯度涂层中的8%Y2O3部分稳定ZrO2组元在等离子喷涂后的快速凝固和冷却过程,发生了c→t’非扩散型相变的c→t扩散型相变,以及少量的t→m相变。涂层中ZrO2主要由未转变的c相及转变产物t相和t’相组成,并存在少量的m相。 相似文献
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氧化硼掺杂钛酸锶钡梯度陶瓷致密化及介电性 总被引:2,自引:1,他引:2
研究了氧化硼(B2O3)掺杂量及烧结温度对钛酸锶钡(Ba1-xSrxTiO3,x=0~0.4)致密化行为及其微观组织的影响,确定了不同成分钛酸锶钡中氧化硼掺杂量.随后,采用一系列Ba1-xSrxTiO3掺杂粉体,烧结制备了钛酸锶钡梯度陶瓷,并测试了其介电性能.结果表明,钛酸锶钡掺杂适量氧化硼明显降低烧结温度,在1300℃即可烧结致密化,比未掺杂相同成分的钛酸锶钡陶瓷烧结温度至少降低100℃;烧结后各成分单层陶瓷与梯度陶瓷介电性能随温度的变化表明,梯度组成陶瓷的居里峰温度区间显著展宽,大大降低了该温区的介温系数,可望提高该系列陶瓷元器件精度及稳定性。 相似文献
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1 INTRODUCTIONAtpresent ,thehydroxyapatite (HA )andtheHA basedcompositecannotbeusedforheavyload bearingapplicationsashardtissuereplacementim plantsbecauseoftheirpoormechanicalproperties[1] .Ontheotherhand ,theHAcoatingsusedtoimprovethesurfacebioactivityofTia… 相似文献