Ce对铝青铜合金粉体材料涂层微观组织结构的影响

利用等离子喷焊技术,将自主研究开发的多元铜合金粉体(含Ce和不含Ce)涂覆在45等对熔覆层表面微观组织观察,采用X射线衍射、表面EDS、EPMA等分析手段,研究Ce在多元铝青铜粉末熔覆层中的分布及其对微观组织结构的影响.结果表明:稀土Ce在多元铝青铜合金粉体材料涂层中以化合物的形式存在,主要富集在晶界,少量分布在晶粒内...     

铝合金大厚板淬火残余应力数值分析

基于淬火会引起铝合金大厚板很大的残余应力,并容易引起淬火变形与裂纹,恶化材料的性能,运用有限元分析软件ANSYS研究了铝合金板材尺寸、淬火介质温度对温度场、应力场和残余应力的影响.基于随温度变化的材料物性参数以及材料表面与淬火介质的换热系数,进行了淬火过程的非线性热传导分析.结果表明,随着板材厚度的增加,铝合金薄板的残余应力增加明显,而铝合金厚板的残余应力未产生太大变化;随着淬火介质温度的升高,厚板的残余应力也无明显降低;对于铝合金厚板,通过优化合金成分等措施来提高合金淬透性,才能有效降低残余内应力,并保证合金的力学性能.     

Improving the tensile properties of extruded Mg–Ga alloy by ageing treatment

A hot-extruded Mg-5Ga alloy was subjected to ageing treatment at 150 ?°C, 190 ?°C and 230 ?°C. The microstructures and mechanical properties of the extruded and aged alloy were examined in this study. Microstructure examinations suggested that particle-shaped and rod-shaped Mg₅Ga₂ were precipitated in the alloy after peak ageing treatment. The extruded alloy showed the yield strength, ultimate tensile strength and elongation to fracture of 157.6 ?MPa, 248.6 ?MPa and 17.5%, respectively. After peak ageing, the yield strength and ultimate tensile strength can be enhanced by as much as 15.7% and 8.6% reaching 182.3 ?MPa and 270 ?MPa, respectively. The improvement of the tensile strengths is mainly attributed to the enhanced precipitation strengthening by newly formed fine Mg₅Ga₂ precipitates. The ductility of the alloy was slightly increased by peak ageing at low temperatures (150 ?°C and 190 ?°C), but remarkably decreased by peak ageing at high temperature (230 ?°C) due to the formation of coarsened Mg₅Ga₂ particles which easily initiated the cracks during tensile deformation.     

稀士元素在导电铜中的作用

本文研究了不同稀土添加剂在导电铜中的作用,发现稀土元素改变了夹杂物的形态,细化了晶粒(但Nd例外),提高了导电铜的机械性能;适量的稀土添加剂改变了导电铜中杂质存在的形态,净化了基体和晶界,改善了导电铜的导电性。     

Effect of pickling processes on the microstructure and properties of electroless Ni–P coating on Mg–7.5Li–2Zn–1Y alloy

The electroless plating Ni–P is prepared on the surface of Mg–7.5Li–2Zn–1Y alloys with different pickling processes.The microstructure and properties of Ni–P coating are investigated.The results show that the Ni–P coatings deposited using the different pickling processes have a different high phosphorus content amorphous Ni–P solid solution structure,and the Ni–P coatings exhibit higher hardness.There is higher phosphorus content of Ni–P amorphous coating using 125 g/L Cr O3and 110 ml/L HNO3(w68%)than using 180 g/L Cr O3and 1 g/L KF during pre-treatment,and the coating structure is more compact,and the Ni–P coatings exhibit more excellent adhesion with substrate(Fcup to22 N).The corrosion potential of Ni–P coating is improved and exhibits good corrosion resistance.As a result,Mg-7.5Li-2Zn-1Y alloy is remarkably protected by the Ni–P coating.     

3D打印铝合金力学性能的非线性超声检测

为了研究非线性超声检测技术评估材料抗拉强度的可行性,对不同成型角度下的3D打印铝合金材料进行非线性超声检测和力学拉伸试验。结果表明材料的抗拉强度、微观缺陷比率和超声非线性系数三者之间有很强的相关性。随着材料微观缺陷比率增大,超声非线性系数也随之增大,而抗拉强度呈现变小的趋势,因此超声非线性系数可以评价材料的强度。此外,对不同成型角度下的3D打印铝合金试件进行疲劳试验,发现疲劳加载后试件的超声非线性系数随着微裂纹萌生而增大。因此,非线性超声检测技术可用于3D打印铝合金材料力学性能的评估和微裂纹的检测。     

橡塑合金改性沥青混合料路用性能研究

为了研究橡塑合金改性沥青混合料的路用性能,采用精密开炼机将废轮胎胶粉和废塑料制备成橡塑合金,对基质沥青及混合料进行改性,采用正交试验确定AC-13型、SMA-13型橡塑合金改性沥青混合料的成型参数,通过车辙试验、浸水马歇尔试验、冻融劈裂试验和小梁弯曲试验,对橡塑合金改性沥青混合料和废轮胎胶粉改性沥青混合料的路用性能进行对比研究。结果表明,AC-13型橡塑合金改性沥青混合料的成型参数分别为油石比4.8%、拌和温度180℃、击实温度165℃;SMA-13型橡塑合金改性沥青混合料的成型参数分别为油石比6.1%、拌和温度185℃、击实温度170℃,与废轮胎胶粉改性沥青混合料相比,橡塑合金改性沥青混合料的高温稳定性和水稳定性更好,但低温抗裂性较差。     

非晶合金变压器设备选型的探讨

阐述了干式非晶合金变压器的特点,分析了无储油柜非晶合金全密封变压器可能出现的隐患,提出了优化的选型方案。     

NiTi形状记忆合金表面多层梯度陶瓷膜的制备

在ＮｉＴｉ形状记忆合金表面采用三步法制备了多层梯度钛酸铅陶瓷薄膜。第一层膜采用原位水热法制备，第二层膜以醇热法制备，第三层膜应用溶胶－凝胶法制得。Ｘ射线衍射研究确认最外层薄膜具有四方钙钛矿结构。扫描电子显微镜观察表明，薄膜总厚度约为３μｍ；由里及外三层膜中的晶粒尺寸依次约为０．１μｍ、０．２μｍ和０．３μｍ。在陶瓷膜与记忆合金基体的界面处可观察到明显的根状结构，而且在三层陶瓷膜之间的界面处也观察到