采用布氏硬度试验、拉伸试验、金相显微镜和透射电子显微镜(TEM)等方法,研究了Mg、Si含量变化对Al-Mg-Si合金力学性能和耐晶间腐蚀性能以及析出行为的影响.结果 表明:随着Mg、Si含量的增加,Al-Mg-Si合金的时效硬化速率显著提高,时效峰值硬度和强度均提高.在峰值时效状态下,高Mg、Si含量的合金的硬度与抗拉强度最高,但其耐晶间腐蚀性能明显降低.高Mg、Si含量的合金在时效过程中晶内析出了大量细小弥散的β"相,晶界析出相呈细小连续分布;低Mg、Si含量的合金晶内析出的β"析出相尺寸较大,晶界无沉淀析出相.

采用2,4和10μm镍箔作为中间层,在1 120℃/4 MPa/60 min焊接条件下,对高温合金GH4099进行固相扩散焊.采用SEM,EDS分析接头形貌演变、元素迁移,并利用拉伸试验测试其力学性能.结果表明,添加镍中间层能促进界面的孔洞闭合.随着镍层厚度由10μm降低至2 μm,界面处出现晶粒共生现象,元素扩散更加均匀,焊缝析出较大尺寸的强化相,接头抗拉强度提高,2 μm中间层接头平均抗拉强度达到1 180MPa.但随着中间层减薄,接头性能对表面粗糙度敏感,拉伸过程中母材对中间层拘束作用使接头塑性变形受到抑制,断后伸长率反而降低.

Effect of two-step aging treatment on mechanical properties and resistance to intergranular corrosion of Al-Mg-Si aluminum alloy were investigated by hardness test,tensile test,intergranular corrosion test and TEM observation.The experimental results showed that the Al-Mg-Si alloy in T6 temper condition had as excellent mechanical properties as hardness of 114 HB,tensile strength of 445.67 MPa,yield strength of 423.75 MPa,and elongation of 11.75％.In addition,the intergranular corrosion depth was 345 μm.After two-step aging treatment,the alloy still had good mechanical properties while the depth of corrosion reduced obviously.As a result,the optimum two-step aging treatment was T6 + (150 ℃/2 h).

Effects of non‐isothermal aging treatment on mechanical properties and corrosion resistance of Al–Mg–Si aluminum alloy were investigated by hardness test, tensile test, intergranular corrosion test, and TEM observation. The results suggested that the NIA process (heating from 30 °C to 190 °C at 20 °C/h) is capable of enduing higher mechanical performances and comparable corrosion resistance to Al–Mg–Si alloys, as compared with that of the T73 condition. The different evolution of precipitates in intra‐grain and grain boundary is supposed to explain the various mechanical performances and corrosion resistance.

提出一种新型切削温度测量装置,比传统测温装置更简单、更方便,准确度高.利用该装置研究正火温度对20CrNiMo齿轮钢显微组织和切削性能的影响.结果表明,随着正火温度的提高,齿轮钢组织中铁素体长大且含量增加.正火温度从850、950℃升高至1 050℃时,刀具切削温度和前刀面磨损量均先下降后上升,切屑为长卷屑且逐渐增长.