Effect of heat treatment on microstructure and tensile properties of A356 alloys

作者：Peng Ji hua^*; Tang Xiao long; He Jian ting; Xu De ying

来源：Transactions of Nonferrous Metals Society of China (English Edition), 2011, 21(9): 1950-1956.

DOI：10.1016/S1003-6326(11)60955-2

• Al-Si casting alloys
• heat treatment
• tensile property
• microstructural evolution

Two heat treatments of A356 alloys with combined addition of rare earth and strontium were conducted. T6 treatment is a long time treatment (solution at 535 degrees C for 4 h + aging at 150 degrees C for 15 h). The other treatment is a short time treatment (solution at 550 degrees C for 2 h + aging at 170 degrees C for 2 h). The effects of heat treatment on microstructure and tensile properties of the Al-7%Si-0.3%Mg alloys were investigated by optical microscopy, scanning electronic microscopy and tension test. It is found that a 2 h solution at 550 degrees C is sufficient to make homogenization and saturation of magnesium and silicon in alpha(Al) phase, spheroid of eutectic Si phase. Followed by solution, a 2 h artificial aging at 170 degrees C is almost enough to produce hardening precipitates. Those samples treated with T6 achieve the maximum tensile strength and fracture elongation. With short time treatment (ST), samples can reach 90% of the maximum yield strength, 95% of the maximum strength, and 80% of the maximum elongation.

• 单位
  华南理工大学