无匙孔搅拌摩擦点焊组织及剥离性能研究

针对2 mm的6082-T6铝合金薄板以搭接的方式进行无匙孔搅拌摩擦点焊,研究了工艺参数对剥离性能的影响规律,观察分析接头的金相组织和断口,并对接头进行了显微硬度的测试。通过正交工艺试验来确定无匙孔搅拌摩擦点焊十字搭接接头的最优工艺参数,研究结果表明:焊接接头的横截面宏观形貌呈瓢状,从焊接接头中心到母材,其金相显微组织可分为搅拌区、轴肩区和母材区;点焊接头的抗剥离载荷在最优工艺参数下可达5.24 kN;断口的断裂形式为韧性断裂。     

铝锂合金FSW焊接接头性能

研究2060铝锂铝合金FSW焊接接头性能,采用光学显微镜、SEM等手段分析2060铝锂合金的微观组织、拉伸性能、显微硬度、断口形貌等性能,结果表明:在用FSW焊接2060铝锂合金过程中,当转速升高时,焊核区硬度升高;当焊速升高时,焊核区硬度基本不变,但热影响区硬度最低点向远离焊核区中心的方向移动;较高的焊接速度下(200 mm/min),随转速增加,接头强度逐渐升高,强度系数最高可达到89%;在较低焊接速度下(80 mm/min),随转速的增加,接头强度最高可达母材的87%,延伸率为10%;当转速较低时,断口呈层状结构;当转速较高时,断口出现小的韧窝。     

LF6铝合金搅拌摩擦焊焊缝中S曲线对接头拉伸性能的影响

在铝合金搅拌摩擦焊中,当焊接规范参数选取不当时,焊缝中会出现一种S形曲线。采用圆柱右螺纹搅拌头,对铣去对接面氧化膜和不铣去对接面氧化膜的试样分别进行搅拌摩擦焊试验,研究焊缝中S线对接头性能的影响。结果表明:焊缝中的S线对接头的拉伸性能有影响。含有S线的试样沿焊缝上的S线断裂,断面呈"S"状;焊缝中无S线的试样在焊核中断裂,断面呈45°。焊缝中的S线使接头的强度下降。     

5083铝合金搅拌摩擦焊研究

试验研究了3.5mm厚铝合金5083-H321搅拌摩擦焊工艺,分析了焊接参数对焊缝成型、力学性能和金相组织的影响。结果表明,5083-H321铝合金具有良好的搅拌摩擦焊接性能,采用优化的工艺参数可以使焊接接头的抗拉强度达到母材的93.6%,正弯和背弯角度均可达到180°。     

飞机铝合金型材结构FSW焊接

提出了搅拌摩擦焊接（Friction Stir Welding,FSW）技术的3个基本要素,对铝合金型材FSW焊接件在航空结构中的几个典型应用进行了分析.并简要介绍了中国搅拌摩擦焊中心在铝合金型材搅拌摩擦焊接方面的研究成果.中国搅拌摩擦焊中心的研究表明,采用搅拌摩擦焊技术焊接铝合金能够得到比较满意的接头强度.     

Process of friction-stir welding high-strength aluminum alloy and mechanical properties of joint

The process of friction-stir welding 2A12CZ alloy has been studied. And strength and elongation tests have been performed, which demonstrated that the opportunity existed to manipulate friction-stir welding parameters in order to improve a range of material properties. The results showed that the joint strength and elongation arrived at their maximums ( 331 MPa and 4% ) at 37. 5 mm/min and 300 rpm. As welding parameters changing, joint tensile strength and elongation had similar development. Hardness measurement indicated that the weld was softened. However, there was considerable difference in softening degree for different joint zone. The weld top had lower hardness and wider softening zone than other zone of the weld. And softening zone at advancing side was wider than that at retreating side.     

ZL114A铸铝搅拌摩擦焊接头性能

研究了采用不同焊接参数时ZL114A铸铝搅拌摩擦焊接头的金相组织、硬度分布及力学性能。结果表明，ZL114A铸铝的搅拌摩擦焊焊接性良好。焊核区的微观组织是无方向性的、细小的等轴晶粒。细化的硅粒子均匀布满整个焊核区。与粗大的树枝状母材相比，焊核晶粒细小、均匀而致密，没有观察到气孔等缺陷。焊缝区硬度分布较母材稳定，变化范围小。随着焊速增加，硅粒子所占体积比逐渐下降。热一机械影响区晶粒被拉长。接头的力学性能与焊接参数的匹配有关系。采用高焊速及转速与焊速比在3左右，获得的接头抗拉强度可达到母材的91％。焊后经T6热处理，可与同炉热处理母材等强。     

Effect of natural aging on microstructure and mechanical properties of friction stir welded 7050-T7451 joints

The microstructure and mechanical properties of friction stir welded 2.5 mm 7050-77451 aluminum alloy natural aging 72 h and 17 520 h were investigated,respectively.The uniaxial tensile test showed that yield strength,tensile strength and elongation of the joints 17 520 h natural aging were about 20%,12%and 24%higher than those joints natural aging72 h.Hardness profile of natural aging 17 520 h joint witnessed significant enhancement in nugget zone,compared with 72 h natural aging.Differential scanning calorimetry(DSC) and transmission electron microscopy(TEM) test revealed that more Guinier-Preston zone,η' and η phase emerged in nugget zone as natural aging duration increased,high density of dislocation located within grain boundary in nugget zone of joints natural aging 72 h.It is concluded that natural aging was feasible to enhance strength and plasticity of FSW joints simultaneously.     

6082-T6铝合金回填式搅拌摩擦点焊接头的疲劳性能的有限元分析

利用有限元分析软件ANSYS模拟了6082-T6铝合金回填式搅拌摩擦点焊接头在不同载荷作用下的应力场,进而分别运用名义应力法和局部应力-应变法计算得到当前载荷水平下的疲劳寿命。结果表明:在较大的载荷水平下,应力法分析结果与试样实际寿命接近,在较小的载荷水平下,局部应力-应变法分析结果与试样实际寿命接近;试样疲劳寿命随焊点间距的增加而减小。通过分析6082-T6铝合金回填式搅拌摩擦点焊接头疲劳断口形貌,发现疲劳裂纹起裂于焊点根部的热影响区和热力影响区,同时沿上板焊点边缘和下板母材处横向扩展。     

30 mm 7A05铝合金搅拌摩擦焊接头组织及力学性能

采用搅拌摩擦焊方法利用新型搅拌头对30 mm厚的7A05-T6铝合金进行了单道对接,焊后分析讨论了焊缝接头微观组织和力学性能.结果表明,接头焊核区发生动态再结晶,生成细小的等轴晶粒;焊缝两侧热力影响区受机械和热的双重作用,组织存在较大差异,前进侧为窄条状组织,后退侧为扁平状组织;热影响区晶粒粗化;在焊接30 mm板时,工艺参数范围较窄,旋转频率为360 r/min,焊接速度为100 mm/min时,可获得无缺陷、成形好的焊缝;接头抗拉强度为367.7 MPa、屈服强度为280.8 MPa、断后伸长率为14.4%高于母材,接头抗拉强度可达母材的95%.接头显微硬度的分布呈类似W形分布,热影响区软化趋势比较明显.