7075铝合金的淬火敏感性(英文)

7075铝合金广泛用于要求高力学性能的零部件。有关技术文献指出,该合金的耐蚀性和力学性能主要决定于淬火冷却速度。这种现象通常称为"淬火敏感性"。本文的主要目的是,通过改变热处理工艺参数和轧制方向(L,LT,ST)来研究板材试样的淬火冷却速度对其性能的影响。试样均在实验室设备中热处理,以获得T6、T76和T73处理状态。试样为长方体(13 mm 13 mm 100 mm),水淬,通过改变水温或改变温度为20℃、用水搅动的浴槽中聚合物浓度来调节淬火冷却速度。在每种实验条件下,均采用置于试样中的热电偶测量冷却速度。此外,还进行了有限元(FEM)模拟试验,以测定所有试验条件下冷却过程的热传递系数;进行了拉伸试验和晶间腐蚀试验,以弄清所研究的冷却速度对7075合金板材性能的影响。

The "Quench Sensitivity" of 7075 Aluminum Alloy Plates

7075 aluminum alloy is widely used especially in those applications for which high mechanical performances are required.In the technical literature it's well known that the corrosion resistance and the mechanical properties of this material strongly depend on the cooling rate during quenching.This phenomenon is known as "quench sensitivity".The main aim of this paper is to investigate the influence of the cooling rate during quenching of samples taken from plates by varying the parameters of the heat treatment and the rolling direction (L,LT,ST).All the samples were heat treated in laboratory equipment to reach T6,T76 and T73 tempers.The samples were prisms (13 mm×13 mm×100 mm) and were quenched in water;the cooling rate was imposed by changing the water temperature or changing the polymer amount in a water agitated bath at 20℃.In each of the experimented condition the cooling rate was measured by a thermoeouple placed in the sample.Moreover a FEM simulation was carried out in order to estimate the heat transfer coefficient during the cooling in all the experimented conditions.Tensile and intergranular corrosion tests were performed to point out the influence of the investigated cooling rates.