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珠光体钢丝冷拉拔过程中微观组织及铁素体微区取向与织构演变张晓丹1,1,刘伟1,刘庆2(1.北京市清华大学材料科学与工程系2.重庆大学 材料学院)摘 要:采用电子通道衬度(ECC)和电子背散射衍射(EBSD)技术研究了珠光体钢丝冷拉拔过程中微观组织的变化,铁素体微区取向与织构演变,结果表明,珠光体变形组织中存在剪切带(S带),它们的出现与渗碳体片条和拉拔方向之间的夹角有关:夹角越大,S带越多,随着拉拔应变量的增大,纵截面上珠光体片条逐渐转向拉拔方向,S带方向与拉拔方向的夹角逐渐减小,珠光体内的S带会引起铁素体晶粒......
等通道转角挤压过程中fcc金属的微观结构演化与力学性能吴世丁1,安祥海1,韩卫忠1,屈伸1,张哲峰1(1.辽宁省沈阳市科学院金属研究所沈阳材料科学国家(联合)实验室)摘 要:系统总结了面心立方(fcc)金属材料在等通道转角挤压(ECAP)变形后的晶粒细化,微观结构演化规律和力学性能.根据ECAP变形的特点,利用具有特殊取向的Al单晶体和Cu双晶体,经过一道次ECAP挤压发现:材料在ECAP模具对角面附近发生严重塑性变形;除了沿模具对角面切应力的作用外,沿垂直于模具对角面的切应力也起重要作用.此外,通过设计特殊取......
冷却速率对GWZ1032K合金中14H-LPSO结构形成的影响张松1,2,袁广银3,卢晨3,丁文江3(1.上海市上海交通大学材料科学与工程学院轻合金精密成型国家工程研究中心 2.上海市上海交通大学材料科学与工程学院国家金属基复合材料重点实验室3.上海交通大学 材料科学与工程学院 轻合金精密成型国家工程研究中心)摘 要:采用金属型铸造和慢速凝固,在不同冷却速率下制备了Mg-10Gd-3Y-1.8Zn-0.5Zr(质量分数,%)(GWZ1032K)合金.采用SEM,TEM和XRD研究了冷却速率不同的GWZ1032K......
Sr对Mg-9Al-1Si-0.3Zn合金微观组织和力学性能的影响邹志文1,熊守美1(1.北京市清华大学机械工程系汽车安全与节能国家重点实验室)摘 要:研究了Sr元素对Mg-9Al-1Si-0.3Zn(质量分数,%)合金晶粒大小,力学性能和Mg2Si形貌的影响.利用深腐蚀方法获得了Mg2Si细化前后的形貌,通过其形貌变化规律研究了Sr元素对Mg2Si细化的机制.结果表明,Sr通过抑制Mg2Si生长使汉字状和加料斗形状的Mg2Si变成规则的正八面体.当Sr的添加量达到0.32%时,Mg2Si的形貌得到了最好的改善......
DOI: 10.11817/j.issn.1672-7207.2020.10.008 后,需要求解的机构运动学反解参数为d1,d2和.由于机构自由度数目大于动平台自由度数目,此时,运动学反解有无穷多个.为了得到唯一运动学反解,首先给定1个驱动参数d1.动平台3个顶点在动坐标系p-uvw下记为,动坐标系p-uvw下的三维坐标()写为矩阵形式为 (1) 通过坐标变换公式(2),可以得到动平台3个顶点(i=1,2,3),在定坐标O-xyz下的三维坐标写为矩阵的形式为: (2) 式中:为动平台位姿的齐次变换矩阵, 求解式(2)可得动平台3个顶点(i=1,2,3)在定坐标系下的三维坐标的具体矩阵形式为:......
orientation and grain size analysis were conducted using electron backscatter diffraction (EBSD, FEI NanoLAB, 600i). Tensile samples were carefully cut into a dog-bone shape and then ground and polished... 6(a) depicts grain orientation maps of SLM sample with clear grain morphology and size; grains with the same color in the figure have the same orientation. In Figure 6(a), a scanning track is clearly......
at various strain amplitudes from 1×10-5 to 8×10-3. For the measurements of temperature dependence of damping capacities, the testing conditions were as follows: the strain amplitude 5×10-3... the strain dependence of damping capacity of ZK60-xY alloys. From Fig.4, it is clear that the curves can be divided into two areas: in the first area, the amplitude of strain is small, and damping......
; Fig.1 Normalized hysteresis loop(a) and MR curves(b) for Si(100)/Cr 5nm/Co 5nm/Si 2.7nm/Co 5nm Fig.2 Saturation resistivity ρs dependence of sandwiches Si(100)/Cr 5nm/Co 5nm/Si...[5-14, 16, 17]. It is also true in our case of Co/Si interface. Fig.2 shows the saturation resistivity dependence of the Co/Si/Co sandwiches on the nominal Si spacer thickness. In Fig.2, it is easy......
dependence of the flow stress on processing parameters, titanium alloys are more difficult to deform than the ferrous metals. Consequently, more care must be taken during hot procedure in order to obtain... A statistical analysis for the orientation of the prior beta grain boundaries cavities nucleated with respect to compression axis is shown in Fig.4, which covers data of 50 boundaries......
)), and the α2/γ lamellar structure shows no obvious orientation after being tested at 700 °C, as shown in Fig. 6(c). However, when the specimen is tested at 850 and 1000 °C, the γ grains are elongated... deformability. The yield stress is low when the load direction lies close to the lamellar plane (soft orientation) and is high when the load direction is nearly normal to the lamellar plane (hard......
