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采用碳纳米管孕育块铸造法制备多壁碳纳米管/AZ31镁基复合材料,经等径角挤压(ECAP)变形后对复合材料在3.5%NaCl(质量分数)的腐蚀介质中进行静态浸渍试验和电化学极化曲线测定,研究等径角挤压变形工艺对复合材料抗腐蚀性能的影响;利用数码相机、扫描电子显微镜对复合材料腐蚀前后的表面形貌进行观察和分析;并对复合材料的抗腐蚀机理进行分析。结果表明:等径角挤压变形工艺能有效的提高多壁碳纳米管(CNTs)/AZ31复合材料的抗腐蚀性能,经等径角挤压变形4道次后,复合材料的平均腐蚀速率由挤压态的0.6035mg/(m2·s)降为0.2963mg/(m2·s)。腐蚀电流密度Icorr由ECAP变形前的3.363μA/cm2减小到2.269μA/cm2。 相似文献
13.
ECAP制备的亚微米7050铝合金的力学性能和微观结构 总被引:8,自引:3,他引:8
采用等通道角挤压法 (ECAP法 )制备亚微米 70 5 0铝合金。为了提高合金的力学性能 ,在挤压过程中增加了固溶时效处理工艺 ,并对 70 5 0铝合金在不同处理工艺条件下的显微组织和力学性能的变化进行了研究。结果表明 :ECAP挤压后进行固溶和时效处理能明显提高合金的力学性能。退火态合金经过ECAP后 ,晶粒尺寸明显细化到亚微米级。将挤压一次的试样进行固溶处理和时效处理 ,合金的强度在 5 75MPa左右 ,而延伸率能达到2 5 .5 %左右 ;若经等通道角挤压过的试样在固溶处理后立即进行再次挤压 ,并配合时效处理 ,合金强度能迅速达到 6 16MPa ,延伸率为 16 .9%。 相似文献
14.
15.
J.‐H. Jiang A.‐B. Ma F.‐M. Lu N. Saito A. Watazu D. Song P. Zhang Y. Nishida 《工业材料与腐蚀》2011,62(9):848-852
Ultrafine‐grained (UFG) Al‐11mass%Si alloy, processed by multi‐pass equal‐channel angular pressing (ECAP) at 573 K, was investigated on corrosion behavior in 0.6 M NaCl solution. Potentiodynamic polarization tests and scanning electron microscopy observation showed that a large number of ECAP passes resulted in lower corrosion current density, more positive corrosion potential, and rather smooth corroded surface with shallow corrosion pits. The uniform distribution of fine secondary‐phase particles on UFG Al matrix weakened the susceptibility to pitting corrosion while inhibited general microgalvanic reactions. The present results indicate that grain refinement of aluminum matrix to the UFG state and uniform redistribution of broken particles (including eutectic silicon and secondary phases), via severe plastic deformation at elevated temperature undergoing dynamic recrystallization, can significantly improve the corrosion resistance of Al alloys, besides the known exceptional mechanical advantages. The simple and effective ECAP procedure makes UFG Al alloys more attractive for high strength structural application in corrosive environment. 相似文献
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ECAP工艺细化铁基形状记忆合金研究 总被引:2,自引:0,他引:2
研究等通道转角挤压(equal channel angular pressing,简称ECAP)技术细化Fe基形状记忆合金。研究结果发现,300℃下Fe-17.8Mn-4.73Si-7.80Cr-4.12Ni(wt%)第一道次挤压力为78kN,与理论计算值70.6kN接近;第二道次挤压力上升明显,达到240kN。金相观察显示挤压后的合金晶粒沿剪切方向拉长,TEM分析显示700℃退火30min后再结晶形成0.3μm左右细小晶粒,与未挤压试样相比晶粒明显细化。ECAP挤压极大的提高了材料的力学性能,屈服强度由未挤压时220MPa提高到挤压后的890MPa;挤压后退火的合金恢复率略有提高,在预变形ε=6.5%时,获得η=74%的形状恢复率。 相似文献
18.
Xu Shubo Zhao Guoqun Wu Xin Ma Xinwu Guan Yanjin 《Frontiers of Materials Science in China》2007,1(2):187-196
Equal channel angular pressing (ECAP) has the capability of producing ultra fine-grained (UFG) materials bellow the dimension
of 1 μm. At present, it is one of the most important methods to get bulk UFG materials. Multi-pass ECAP processes for round
workpieces are investigated by using numerical simulations and experimental studies in this paper. The deformation mechanism
of ECAP for grain refinement is obtained. Three processing routes A, B and C are simulated in order to study the influence
of the processing routes to the deformation uniformity of the workpiece. The finite element (FE) analysis results of the multi-pass
ECAP process show that the different processing routes result in the different deformation distributions. The grain in the
workpiece is refined obviously after multi-pass pressing. The microstructures of the processed material are more different
than that of the microstructure of the annealing initial equiaxed grains. The microstructure evolution of the workpiece can
be changed via different processing routes. It is found that route B can get a high angle grain boundaries distribution in
the workpiece than other routes. The results of the analysis show that the process of grain refinement can be described as
a continuous dynamic recovery and recrystallization. The microstructure evolutions of the grain refinement mechanisms and
micro-structural characteristics for different multi-pass ECAP processing routes are verified by using OM (optical model)
and TEM (transmission electron microscope) analysis. In addition, the experimental microstructure results are also consistent
with FE analysis results. 相似文献
19.
The effect of microstructure on corrosion behaviour of an Al-5.4 wt% Ni alloy fabricated by equal-channel angular pressing (ECAP) was investigated by means of potentiodynamic polarization test. The Al-5.4 wt% Ni alloy samples were severely deformed by ECAP with two strain introduction methods of route A and route BC and the ECAP process was repetitively carried out up to 6 passes (strain 6). The anodic polarization measurements indicated that pitting potential of the ECAPed Al-Ni alloy samples in chloride containing neutral buffer solution increased with ECAP passes. The pitting corrosion resistance of Al-Ni alloy after ECAP by route BC was better than that by route A. It is attributable to that the size of α-Al crystal region was reduced with ECAP passes and route BC was able to obtain more homogeneous α-Al/Al3Ni structure than route A. On the other hand, pitting corrosion resistance of pure Al samples showed an obvious declining with increasing ECAP passes. It was indicated that more homogeneous and finer α-Al/Al3Ni structure obtained by ECAP played a vital role on improving the corrosion resistance of Al-5.4 wt% Ni alloy. 相似文献
20.
旨在探讨等通道转角挤压(equal-channel-angular-pressed,ECAP)对生物医用Mg-3Zn-0.2Ca合金的显微组织以及腐蚀行为的影响。对铸态Mg-3Zn-0.2Ca合金进行了1,2,4道次的剪切挤压变形。采用光学显微组织观察、X射线反射法、电化学等手段研究了挤压道次对镁合金显微组织、织构以及腐蚀行为的影响,也特别关注了ECAP对试样的不同截面方向的显微组织演变以及模拟体液(simulatedbodyfluid,SBF)电化学腐蚀行为的影响。结果表明:ECAP变形后铸态Mg-3Zn-0.2Ca镁合金晶粒逐渐细化,变形后镁合金呈现出与挤压方向呈一定角度的002面剪切织构;随着挤压道次增加,合金的耐蚀性先增加后降低。等通道转角挤压对合金耐蚀性的影响是晶粒尺寸、晶体缺陷和织构变化的综合效果;ECAP变形后合金不同截面方向呈现不同的耐蚀性,垂直于挤压方向截面的耐蚀性优于另2个方向截面的耐蚀性。 相似文献