析出强化锡青铜时效硬化研究

Study on the Age Hardening of Precipitation Strengthened Tin Bronze

采用真空离心铸造方法制备了析出强化ZCu Sn10Zn2Fe Co合金试样,经780℃下保温4 h后水淬固溶处理,随后在时效处理温度300℃、400℃、500℃、600℃下各保温4 h,利用扫描电子显微镜(SEM)分析了铸态、固溶态以及时效处理后合金中析出富含铁、钴粒子的分布规律,并测量了各状态下的硬度。结果表明:合金中析出富含Fe、Co的富集相粒子,固溶处理后合金的硬度最低,随着时效处理温度的升高,析出相数目增多,分布更为弥散均匀,硬度先升高后降低,400℃时达到最大值HB134.4,与铸态ZCu Sn10Zn2Fe Co合金的硬度值HB103.6相比提高了29.7%,之后硬度急剧下降,发生了过时效。

The precipitation strengthened ZCuSn 10Zn2FeCo alloy which was prepared by vacuum centrifugal casting process, has been carried out solution treatment by water quenching after thermal insulating at 780 ℃ for 4 h and then been thermal insulated for 4 h at each aging temperature of 300 ℃, 400 ℃, 500 ℃, 600 ℃. This paper releases the distribution rules of the precipitated iron and cobalt particle in the alloy at its as cast, solution precipitation and aging treatment status by SEM method. The hardness values of the alloy at the every status were measured. The results show that the alloys with Fe, Co rich phase particles has the minimum hardness after solution treatment and with the increase of the aging temperature, the number of precipitates also increases and the distribution is more dispersed evenly and the hardness first increased and then decreased and at last reach its maximum value of HB134.4 at 400 ℃ . Compared with the hardness value of HB103.6 of as-cast ZCuSn10Zn2FeCo alloy, this maximum hardness value is increased by 29.7 %. When the aging temperature is more than 400 ℃, the hardness value decreases rapidly, which is over-aging treatment.