C_2Cl_6、Ba复合处理对AZ91镁合金组织和力学性能的影响

研究了C2Cl6、Ba复合处理对铸造AZ91镁合金组织和性能的影响。C2Cl6高温分解生成C,而C与Al反应生成Al4C3,起到异质形核的作用,细化合金晶粒;Ba聚集在固液相界面之间,阻碍晶粒长大以细化晶粒。试验结果表明,AZ91镁合金经过Ba和C2Cl6复合处理后组织得到明显细化,平均晶粒减小到30μm,与未处理过的合金晶粒(94μm)相比,减小了68.1%;合金的综合力学性能得到了提高,抗拉强度提高了25.6%,伸长率提高了10.3%。

2024铝合金与AZ91镁合金的C_(2)Cl_(6)除气研究

对比研究了C_(2)Cl_(6)对2024铝合金及AZ91镁合金的除气效果。结果表明,2024铝合金及AZ91镁合金的最高除气率可分别达44.8%及41.8%,此时熔体含氢量分别达到0.096 cm3/(100 g)和11.3 cm3/(100 g)。就添加量而言,AZ91镁合金比2024铝合金所需的C_(2)Cl_(6)添加量要大一些(前者为2%~3%,而后者约为1%)。C_(2)Cl_(6)对AZ91镁合金有明显的细化效果。并测试和分析了除气后合金的力学性能。除气后,铝合金和镁合金的力学性能均提高。

Effect of ultrasonic field treatment on degassing of 2024 alloy

The 2024 aluminum alloy was prepared with different ultrasonic processes.Effects of ultrasonic treatment parameters including ultrasonic power,treatment time,treatment temperature,and frequency resonance,as well as C_(2)Cl_(6) degasser on degassing of the 2024 aluminum alloy were investigated.Results indicate that increasing ultrasonic power at the same ultrasonic treatment time can improve the degassing effect.The optimum degassing efficiency can be obtained under the resonant ultrasound condition.With the combination of 1%C_(2)Cl_(6) addition and 150 W ultrasonic treatment for 40 s,the hydrogen content of the alloy is decreased by 52.9%.At the same time,the tensile strength and elongation are increased by 28.3%and 92.3%,respectively,and the yield strength is slightly increased by 6.7%.The degassing mechanism is also discussed.

六氯乙烷对AZ91镁合金熔体除氢及晶粒细化的影响

研究了C_2Cl_6对AZ91镁合金除氢及细化的影响。结果表明,C_2Cl_6对AZ91镁合金有很好的除氢效果,最高除气率可达41.8%。此时,AZ91合金最低含氢量为11.3 cm^3/100g,其室温拉伸力学性能为Rm=208 MPa,R0.2=137 MPa,A=5.3%,抗拉强度和屈服强度比未除氢时分别提高32.5%和7.9%;当C_2Cl_6添加量为2%时,AZ91合金晶粒最细小,其平均尺寸可达120μm。在本实验中,处理AZ91镁合金所需C_2Cl_6最佳添加量约为2%~3%。

不同除气方法对2024铝合金氢含量及力学性能的影响

研究了C_(2)Cl_(6)除气、超声除气、C_(2)Cl_(6)-超声联合除气、氩气除气对2024铝合金氢含量及力学性能的影响。发现C_(2)Cl_(6)-超声联合除气后合金氢含量最低,对应的力学性能最高;研究了2024铝合金氢含量与力学性能的相关性。结果表明,铸锭抗拉强度随氢含量降低而升高,当每100g铝的氢含量小于0.12cm^(3)时,屈服强度随氢含量的降低升高不显著。