Influence of heat treatment on tribological behaviors of novel wrought aluminum bronze

1　ＩＮＴＲＯＤＵＣＴＩＯＮＡｌｕｍｉｎｕｍｂｒｏｎｚｅｐｏｓｓｅｓｓｅｓｅｘｃｅｌｌｅｎｔｐｈｙｓｉｃａｌ,ｍｅｃｈａｎｉｃａｌａｎｄｔｒｉｂｏｌｏｇｉｃａｌｐｒｏｐｅｒｔｉｅｓ .Ｉｔｉｓａｖａｉｌａｂｌｅｆｏｒｍａｋｉｎｇｗｅａｒ ｒｅｓｉｓｔｉｎｇａｎ     

半连续铸造法制备AlCu/Al梯度材料

提出了一种制备梯度材料的双流浇注连续铸造新方法 ,采用该方法在自制的半连续铸造装置上进行了AlCu/Al梯度合金的探索试验。分析了制备合金的组织和性能特点。结果说明 :采用半连续铸造方法在Al Cu系合金中可以实现合金成分随铸件横截面的连续梯度变化 ;合金的成分、显微组织和力学性能之间有较好的对应关系。     

连续铸造技术的发展概况及展望

回顾国内、国外连续铸造技术的发展概况；指出开发和完善“近终形连铸”、“单晶连铸”、“高效连铸”、“连铸坯热送热装”等技术和基于连铸技术研制新型材料是连铸技术发展的主要方向。     

Rapidly solidified hypereutectic Al-Si alloys prepared by powder hot extrusion

Rapidly solidified hypereutectic Al-Si alloys were prepared by powder hot extrusion.By eliminating vacuum degassing procedure.the fabrication routine was simplified.The tensile fracture mechanisms at room temperature and elevated temperature were investigated by SEM fractography.Compared with KS282 casting material,the tensile strength of rapidly solidified Al-Si alloy is greatly improved due to silicon particles refining while its density and coefficient of thermal expansion are lower.than those of KS282.The wear resistance of RS AlSi is better than that of KS282.     

超声振动和挤压压力作用下含0.6%Fe Al-Cu合金的 显微组织和力学性能

采用光学显微镜（OM）、扫描电子显微镜（SEM）和能谱（EDX）、图像统计以及拉伸试验等手段,研究超声振动（UT）和挤压压力（P）联合作用对铸态Al-5.0Cu-0.6Mn-0.6Fe合金显微组织和力学性能的影响。结果表明,P + UT工艺对处理和α-Al、富铁相和Al2Cu的形貌和尺寸有显著影响,富铁的金属间化合物,促进α-Al形貌由树枝状向球状转变,降低了α-AlAl6(FeMn)和Al2Cu相的尺寸。P + UT工艺有利于减少压力作用下经常出现的双峰组织和晶界偏析。P + UT工艺下得到最好的铸态力学性能：抗拉强度（UTS）：268 MPa,屈服强度（YS）：192 MPa,伸长率：17.1%,分别比重力铸造的合金高为64%、59%和307%。     

Fe含量对挤压铸造Al-3.5Mg-0.8Mn合金组织性能的影响

采用拉伸和硬度测试、扫描电镜和X射线衍射仪等手段,研究了不同Fe含量对挤压铸造Al-3.5Mg-0.8Mn合金显微组织和力学性能的影响。结果表明,Fe能改善合金的力学性能,合金中只存在Al₆(FeMn)相。合金的抗拉强度和屈服强度随着Fe含量的增加而增大,伸长率随着Fe含量的增加而降低,原因是随着Fe含量增加,硬脆的Al₆(FeMn)相增多。在挤压压力为75MPa和Fe含量为0.5%时,合金的综合力学性能最佳,其抗拉强度为252MPa,屈服强度为128MPa,伸长率为28%。     

Microstructure and mechanical property of 2024／3003 gradient aluminum alloy

2024/3003 gradient aluminum alloy was prepared by semi-continuous casting using double-stream-pou-ring technique. The microstructures of the as-cast, pressed and heat-treated alloys were analyzed by scanning elec-tron microscope and transmission electron microscope. And the mechanical properties of the alloy in pressed and heat-treated states were studied. The results show that the ingots with diameter of 65 mm and external thickness about 5.5 mm are obtained when the temperatures of the melt in the internal and external ladles are 1 023 and 1 003 K, respectively, and the nozzle diameter is 2.0 mm. The microstructures of the as-cast alloy consist of α(AI) θ(CuAl2)q S(Al2CuMg) in the internal region and α(Al) MnAl6 in the external region. The phases found in the internal and external layers coexist in the transition zone. The transition layer is maintained after plastic deformation and heat treatment of the alloy. The tensile strength, yield strength and elongation of the alloy are 300 MPa,132 MPa and 16.0%, respectively, after T6 treatment. The tensile and yield strength are increased by 150.0% and 94.1%, respectively, compared with that of 3003 aluminum alloy. The maximum hardness in the internal region of 2024/3003 gradient aluminum alloy can be increased from HRF 55 in the pressed state to HRF 70 in the heat-treated state.     

镁合金疲劳的研究进展

对近年来有关镁合金疲劳的研究进行了总结,考察了材料性质、腐蚀介质、高温环境等多种因素对镁合金疲劳性能的影响,并对裂纹萌生及扩展方式进行了分析,归纳了提高镁合金疲劳性能的方法--改善材料质量及表面强化处理或涂层处理,对镁合金疲劳性能的研究进行了展望.     

变形镁合金成形工艺研究及其应用

变形镁合金塑性加工是目前镁合金研究的前沿领域.综述了变形镁合金主要的成形工艺方法及应用领域,介绍了变形镁合金挤压、轧制、锻造、冲压、超塑变形等变形工艺的特点和关键;展望了变形镁合金的应用发展,指出了其成形工艺在军工、汽车、电子、航空航天等领域具有越来越广阔的应用前景.     

稀土在过共晶高硅铝合金中的合金化作用

运用力学性能测试、金相显微镜、扫描电镜研究了稀土在含硅量约为２２％的过共晶Ａｌ－Ｓｉ合金中的合金化作用。结果表明，稀土可作为合金元素替代昂贵金属Ｎｉ，；稀土与Ｃｕ，Ｍｇ，Ｆｅ，Ｓｉ等形成的稀土化合物产生的第二相强化是改善合金高温拉伸性能的主要原因，稀土对合金的强化作用存在一个稀土的最佳含量范围。