研究不具有典型细晶组织的挤压态Mg-7.0Al-0.2Zn(AZ70)合金的超塑性及其变形机制.结果表明:AZ70镁合金具有良好的超塑性变形行为.在380 ℃及1×10~(-3) s~(-1)的最佳变形条件下,最大伸长率为191.5%.380 ℃时具有良好的高应变速率(1×10~(-2) s~(-1))超塑性变形能力,伸长率为161.5%.晶粒尺寸随温度的升高与应变速率的降低而增大.超塑性变形是以晶界滑移为主,表现为变形过程中晶粒组织基本保持等轴,且孔洞沿晶界形成并长大.同时孔洞的长大及连接导致最终断裂,断口形貌显示为典型的韧窝断裂特征.
Superplasticity and deformation mechanism of Mg-7.0Al-0.2Zn(AZ70)alloys without typical fine-grained structure was investigated. It is indicated that the AZ70 alloy exhibits superior superplasticity and the maximum elongation of 191.5% was obtained at 380 ℃ and 1×10~(-3) s~(-1). It is worth mentioned that high-strain-rate ((ε·)＝1×10~(-2) s~(-1)) superplasticity with elongation of 161.5% was achieved at 380 ℃. The mean grain sizes increase with temperature increasing and strain rate decreasing. The grain boundary sliding (GBS) is the dominant deformation mode of the superplasticity, which is verified by grains remaining equiaxial during deformation. Cavities form and grow up along grain boundary. And then the growth and connection of cavities results in the final failure. SEM morphology of the failure surface shows typical tenacity failure characteristics with quantities of uniform dimples.
参考文献
| [1] | 吴立鸿,马全仓,张春香,关绍康,刘旭东.AZ70镁合金的高温流动应力及本构模型[J].稀有金属材料与工程,2008(01):54-57. |
| [2] | 文九巴;杨蕴林;杨永顺.超塑性应用技术[M].北京:机械工业出版社,2005:23. |
| [3] | Wu Xin;Liu Yi .[J].Scripta Materialia,2002,46(04):269. |
| [4] | Zenji Horita;Kiyoshi Matsubara;Koichi Makii;Terence G. Langdon .A two-step processing route for achieving a superplastic forming capability in dilute magnesium alloys[J].Scripta materialia,2002(4):255-260. |
| [5] | Hiroyuki Watanabe;Toshiji Mukai;Mamoru Mabuchi et al.[J].Scripta Materialia,1999,41(02):209. |
| [6] | 徐华阳,张志豪,谢建新.AZ91镁合金齿轮类精密零件超塑性模锻成形研究[J].塑性工程学报,2007(01):58-61,75. |
| [7] | Wesling V;Ryspaev T;Schram A .[J].Materials Science and Engineering A,2007,46(1-2):144. |
| [8] | del Valle JA;Penalba F;Ruano OA .Optimization of the microstructure for improving superplastic forming in magnesium alloys[J].Materials Science & Engineering, A. Structural Materials: Properties, Misrostructure and Processing,2007(1-2):165-171. |
| [9] | GB/T 4338-1995.GB/T 4338-1995[S]. |
| [10] | Tan J C;Tan M J .[J].Scripta Materialia,2002,47(02):101. |
| [11] | 康达昌.超塑性与金属加工技术[M].北京:机械工业出版社,1985:25. |
| [12] | Galiyev A;Kaibyshev R .[J].Scripta Materialia,2004,51(02):89. |
| [13] | 曹剑,张福全,夏伟军,傅定发,陈振华,吴有伍.AZ31镁合金多阶段超塑性变形[J].轻金属,2005(02):58-61. |
| [14] | Ion S E;Hunphreys F J;White S H .[J].ACTA MATERIALIA,1982,30:1909. |
| [15] | Tan M J;Zhu X J;Thiruvarudchelvan S .[J].Journal of Mater Tech,2007,191(1-3):202. |
| [16] | Yin D L;Zhang K F;Wang G F et al.[J].Materials Letters,2005,59:1714. |
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