Xiaodong WANG
,
Baoxu HUANG
,
Yonghua RONG
,
Li WANG
,
null
,
null
,
null
,
null
材料科学技术（英）
Transformation induced plasticity (TRIP) steels combine high strength and excellent ductility, making them suited for application in crash-relevant parts in the automotive industry. However, the high Si contents in the conventional TRIP steel will generate surface defects on the hot rolled strip, which is difficult to process in continuous galvanizing lines. In order to solve the above problem the TRIP steel with the addition of Al replacing majority of Si was designed. In the present paper, the volume fraction of various phases in a C-Mn-Si-Al-Cr TRIP steel was determined by metallographic examination and X-ray diffraction analysis, and the multi-phase microstructures were characterized using an atomic force microscope based on their height difference. Tensile tests were performed at different temperatures ranging from -40℃ to 90℃. The results show that transition temperature MSσ in the present TRIP steel cannot be determined due to its lower volume fraction of retained austenite, different from the conventional TRIP steel. While the yield stress and tensile strength at different temperatures are higher than those of the conventional TRIP steel, which is attributed to the addition of Cr. In order to evaluate the effect of martensitic transformation on the total elongation, the sample without retained austenite obtained by quenching in liquid nitrogen was carried out under tensile test. The results indicate that the elongation of the original sample containing 9% retained austenite is about 20% higher than that of the sample quenched in liquid nitrogen, which demonstrates that the retained austenite plays an important role in improving the elongation of the TRIP steel.
关键词:
TRIP steel
,
steel
,
mechanical
,
properties
,
retaine
陈玉安
,
周彩瑜
稀有金属材料与工程
采用机械球磨法制备Mg17Al12合金,系统研究了球磨时间对Mg17Al12形成过程的影响;并以球磨12h的Mg17A112合金为基体,添加5％、10％(质量分数)的Ni、Cu单质,通过机械球磨对合金进行表面复相改性.采用P-C-T测试仪测定合金的储氢性能,研究添加不同质量分数的单质对Mg17Al12合金储氢性能的影响.结果表明:球磨12 h Mg17Al12的吸氢速率较慢,吸氢时间较长,需在1400 min达到最大吸氢量为4.1％(质量分数),接近其理论吸氢量4.4％,Mg17Al12的吸放氢过程是可逆的.Cu对Mg17Al12进行表面复相改性,可以显著改善其吸氢动力学性能,添加5％Cu和10％Cu的合金在623 K,240 min的吸氢量分别为4.07％和3.9％.经过Cu和Ni复相改性后的Mg17Al12具有较好的放氢性能,添加5％Cu合金在553 K放出3％的氢气.Ni对Mg17Al12进行表面复相改性,对其性能有一定的提高,但是和Cu相比,并不明显.
关键词:
储氢合金
,
Mg17Al12
,
机械球磨
,
物相分析
,
吸放氢性能
张诚
,
宋西平
,
刘敬茹
,
杨云
,
尤力
金属学报
doi:10.11900/0412.1961.2016.00193
采用XRD, OM, BSE, SEM和显微硬度计等手段研究了氘含量对Zr-4合金显微组织及力学性能的影响. 结果表明, 随着氘含量(质量分数)从1.35%增加到2.21%, 氘化物数量增加, 其形态及分布也发生了显著变化: 在1.35%时, 主要以晶内针状氘化物析出为主; 随着氘含量增加, 晶界块状氘化物快速增长; 当氘含量进一步增加至2.21%时, 晶界块状氘化物开始相互衔接, 并逐渐向晶内生长. 在氘含量较高的样品表层, 有一定厚度的氘化物层形成, 且层内出现微裂纹. 所形成的氘化物以δ-氘化物为主, 而高氘含量样品表面有ε-氘化物出现. 样品心部至表面存在一定的硬度梯度, 且随着氘含量的增加, 样品的硬度增加, 其相应的硬度梯度增大. 随氘含量增加, 样品的屈服强度略有增加, 而抗压强度却显著下降, 由1.35%下的1176 MPa降低到了2.21%下的856 MPa. 抗压强度的降低与组织中微裂纹有关. 样品压缩后的裂纹主要沿晶界块状氘化物形成并扩展, 因此晶界块状氘化物是材料压缩性能下降的主要原因.
关键词:
锆合金,
,
氘含量,
,
显微组织,
,
力学性能,
,
氘化物
夏显明
,
薛克敏
,
李萍
,
魏宝丽
有色金属工程
doi:10.3969/j.issn.2095-1744.2017.03.006
对挤压态ZK60镁合金进行往复挤压成形,研究往复挤压后材料的显微组织和力学性能变化规律.结果表明,往复挤压的温度和挤压道次对ZK60镁合金力学性能及显微组织有较大影响,随着挤压温度的提高和挤压道次的增加,ZK60镁合金呈现较高的抗拉强度、较低的屈强比和较大的延伸率等,室温塑性变形性能较好.往复挤压使晶粒明显细化,伴随出现再结晶过程,细晶分布具有一定的流向性.随着挤压道次的增加,晶粒等轴倾向明显,细晶分布趋于均匀化.室温拉伸断口形貌韧窝数量与深度均明显增加,变形能力提高显著.
关键词:
ZK60镁合金
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往复挤压(CEC)
,
显微组织
,
力学性能
周珍珍
,
徐志锋
,
余欢
,
王振军
中国有色金属学报
选用三维五向和三维正交两种编织结构的纤维预制体,采用真空气压浸渗法制备纤维3D-Cf/Al复合材料,研究编织结构对3D-Cf/Al复合材料显微组织和拉伸强度的影响.结果表明:编织结构对3D-Cf/Al复合材料的显微组织与力学性能具有显著影响.其中,三维五向和三维正交Cf/Al复合材料平均致密度分别为97.7％和98.3％,三维五向Cf/Al复合材料存在少量的束间孔洞、气孔缺陷,而三维正交Cf/Al复合材料存在少量纤维团聚缺陷;三维五向Cf/Al复合材料的拉伸强度、拉伸模量及泊松比均明显高于三维正交Cf/Al复合材料的,二者的平均拉伸强度分别为753.5 MPa和644.1 MPa,拉伸模量分别为194 GPa和150 GPa,泊松比分别为0.89和0.04;三维五向Cf/Al复合材料的抗弯强度、弯曲模量均明显低于三维正交Cf/Al复合材料的,二者平均抗弯强度分别为931.8 MPa和1010.3 MPa,弯曲模量分别为134.2 GPa和154.6 GPa.通过对预制体编织结构的设计,可实现3D-Cf/Al复合材料性能设计.
关键词:
3D-Cf/Al复合材料
,
显微组织
,
力学性能
,
真空气压浸渗
