淬火水温对7050铝合金组织性能的影响

Effect of Water Quenching Temperature on Microstructure and Properties of 7050 Aluminum Alloy

摘要:

固溶处理是常见的提升7050铝合金综合性能的热处理手段，但由于7050合金存在一定的淬火敏感性，淬火水温是影响其性能的一个重要因素，不同的淬火水温会影响合金获得的固溶体饱和度和析出相尺寸，进而影响合金性能。研究了固溶处理时，冷却水温度对7050铝合金组织性能的影响。结果表明，随着淬火水温的升高，通过EBSD分析得出合金的大角度晶界比例逐渐提升，位错主要集中在大角度晶界和晶界密集的区域，合金中晶界处不断产生析出相并长大，合金硬度呈现先增加后降低的趋势，耐腐蚀性能随着淬火水温的升高持续变差。50 ℃水温淬火时合金具有良好的综合性能，显微硬度为1707.16 MPa，腐蚀电位为?0.927 V。

Abstract:

Solution treatment is a common heat treatment to improve the comprehensive properties of 7050 aluminum alloys. Due to the quenching sensitivity of 7050 alloy, the water quenching temperature is an important factor affecting its performance. Different water quenching temperatures affect the saturation of solid solution obtained consequently and the size of precipitated phases, which in turn affects the properties of the alloy. The effect of water quenching temperature on the microstructure and properties of 7050 aluminum alloy during solution treatment was investigated. Results show that with increasing the water quenching temperature, the fraction of high angle grain boundaries (HAGBs) in the alloy increases according to the EBSD analysis; dislocations are mainly concentrated in HAGBs and areas with dense grain boundaries (GBs); the precipitated phase of the alloy continuously forms and grows at the GBs; the hardness of the alloy shows a trend of increasing first and then decreasing; the corrosion resistance deteriorates as the water quenching temperature increases. The alloy shows excellent comprehensive properties when quenched in water at 50 °C, with a microhardness of 1707.16 MPa and a corrosion potential of ?0.927 V.