【作者】 宋宪杰；

【导师】 李荣德； 刘敬福；

【作者基本信息】 沈阳工业大学 ， 材料加工工程， 2009， 硕士

【摘要】 本文主要研究了锰含量、轧制工艺、热处理工艺对ZA35合金组织与性能的影响。研究表明:锰的加入可以明显改善锌铝合金的力学性能。随着锰含量的增加,合金的抗拉强度有所增加,锰含量超过0.75%时,合金抗拉强度有所下降;锰合金化可以明显提高合金硬度,1.3%时合金硬度最大;锰的加入降低了合金的塑性,锰含量1.3%时伸长率最低。在再结晶温度相同的情况下,轧制态锌铝合金抗拉强度、硬度增加、伸长率相比于铸态合金都有所提高,随着变形量的增加ZA35合金抗拉强度、硬度提高,但伸长率在变形量达到20%时最大,之后呈减小趋势。变形量为20%时合金的综合性能最佳。相比于铸态合金,抗拉强度提高27.8%达到467MPa、硬度指标提高了36.4%达到127HB、伸长率达到3.6%。随着变形量的增加,合金基体组织逐渐细化、空隙减少、析出相分布均匀,条状、块状的第二相逐渐破碎并且晶粒的取向比较明显,沿轧制方向呈纤维状分布;在轧制过程中,随着再结晶的发生,合金中的含Mn过饱和固溶体发生脱溶,与基体元素Al形成MnAl6;然而变形量过大时组织中出现微裂纹,这是合金塑性降低的原因。适当的热处理工艺可以消除偏析,使析出相均匀分布,大大改善合金的力学性能。固溶温度、固溶时间、时效温度、时效时间对ZA35合金的抗拉强度、硬度、伸长率有显著的影响。对于轧制态ZA35合金来说,365℃～375℃固溶,固溶时间2～3h,120℃时效7～8h时合金的综合力学性能最佳,抗拉强度达到515MPa,硬度170～180HB,伸长率8.0%,明显优于ZA27铸态合金460～470MPa。更多还原

【Abstract】 The effects of Mn content, rolling and heat-treatment on microstructure and properties of ZA35 alloy were studied in this paper.The results show that adding Mn can improve the mechanical properties of the alloy. With increasing amount of Mn, the tensile strength of alloy is improved. The tensile strength of alloy decreases when the content of Mn is over 0.75%; Mn addition can improve the hardness of the alloy. The hardness is the best when the content of Mn is 1.3%; The adding Mn can decrease the elongation of the alloy. The elongation is the lowest when the content of Mn is 1.3%.Under the same recrystallization temperature, the tensile strength, the hardness and the elongation of rolled ZA35 alloy are better than the these at as-cast state. With the increment of strain intensity, the tensile strength and the hardness of ZA35 alloy are improved, but the elongation decreases when the strain intensity is 20%.Compared to the cast state, when the strain intensity reaches to 20%, the tensile strength is 467MPa, which increases up to 27.8%, the hardness is 127HB, which increases up to 36.4%, the elongation is 3.6%.With increasing strain intensity, matrix structure of alloy is refined, voids are reduced、distribution of precipitated phase homogenized;the strip shape and massive shaped second phases are broken, and the grain orientation along the rolling direction distributes lacily. In the rolling process, with the happening of recrystallization, supersaturated solid solution of Mn began to desolate, and form MnAl6 with Al. However, when the strain intensity is too large, crake will appear in the matrix structure, this is caused by the decrease of elongation.Proper heat treatment can eliminate the segregation and obviously improve the mechanical properties of alloy. Solution temperature, solution time, aging temperature and aging time can obviously affect the tensile strength, hardness and elongation of ZA35 alloy. As for the rolled ZA35 alloy, when the solution temperature is 365℃～375℃, solution time is 2～3h, aging temperature is 120℃,aging time is 7～8h,the mechanical properties of alloy are the best. Compared to the as-cast state, the tensile strength increases from 460 to 515MPa, the hardness is 170～180HB,the elongation is 8.0% at the same time.更多还原