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为实现7050铝合金高效优质表面强化,将高速超声引入到二维超声滚压中,研究了7050铝合金高速二维超声滚压后的表面质量。首先采用单因素试验法对7050铝合金进行高速二维超声滚压加工试验,利用超景深测量仪和扫描电镜观察并对比分析了车削后与滚压后的表面形貌和微观组织;采用粗糙度测量仪、显微硬度计和X射线衍射仪测量滚压后的表面粗糙度、显微硬度和表面残余应力,并分析了不同工艺参数对表面质量的影响。结果表明:7050铝合金经高速二维超声滚压加工后,试件表面更为光滑,表层组织更致密,能有效降低表面粗糙度值、提高显微硬度,并形成残余压应力,表面粗糙度最低为0. 68μm,降幅达65%,表面显微硬度最大为156 HV0. 1,增幅达72%,表面残余压应力最高达-329. 5 MPa。在高速二维超声滚压中,7050铝合金工件表面粗糙度主要受静压力和转速影响,表面显微硬度受静压力、进给量和振幅影响较大,而表面残余压应力主要受进给量的影响。7050铝合金加工时表面组织及性能主要受冷塑性变形和温度场的综合影响,高速二维超声滚压加工工艺能够实现7050铝合金的优质高效强化处理。 相似文献
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研究了超声波对铸造7050铝合金的微观组织和时效特性的影响.结果表明,与常规铸造比较,经超声处理的合金具有更加细小的微观组织,且更快达到时效峰值.超声处理7050合金在120℃、时效处理8h后,其强度即可达到峰值,抗拉强度、屈服强度和伸长率分别为602 MPa、547MPa和12.7%.而常规铸造合金,时效处理12 h后,其抗拉强度、屈服强度和伸长率达到峰值,分别为536MPa,462MPa和15.0%. 相似文献
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《特种铸造及有色合金》2017,(2)
对铸造7050铝合金进行均匀化热处理,并对处理后的试样硬度和微观组织进行分析,找出7050铝合金均匀化的最优化生产工艺。结果表明,均匀化处理工艺为480℃×24h;在该热处理工艺下,均匀化处理组织情况较好,过烧较少且硬度较高,晶界处仍含有以Cu为主的未溶第二相,但其形态由初始的块状变为断续的颗粒状。 相似文献
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超声对7050铝合金凝固组织影响的数值模拟 总被引:1,自引:1,他引:0
采用Procast-CAFE模块,建立了7050铝合金形核和晶粒生长的数学模型,模拟了7050铝合金在不同功率超声作用下组织的演化过程。结果表明,随着超声功率增大,熔体形核率增大,晶粒细化效果更好,组织分布更均匀,平均晶粒尺寸更小。模拟结果与试验结果符合。 相似文献
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为解决2219铝合金微观组织粗大、第二相分布不均的问题,开展了对铸态2219铝合金热压缩变形组织演变规律的研究。研究结果表明,经热压缩变形后,铸态2219铝合金组织中粗大的晶粒及连续网状分布的残余结晶相被打碎,经热处理后形成了均匀的再结晶组织。随着变形温度的升高,晶粒组织粗化,但Al2Cu相的分布更细小、均匀;随着变形量的增大,晶粒组织逐渐细化,晶粒大小分布也更均匀,且Al2Cu相也随变形量的增加破碎得更充分,分布更细小、均匀。在大直径铸锭锻造开坯过程中,为了获得Al2Cu相细化分布的组织,变形温度应控制在420℃以上,单次变形量不应低于50%。延长锻后保温时间不会显著影响材料的显微组织,因此,在锻造开坯过程中,为了保证合理的变形温度区间,可以采用回炉加热多火次锻造的方式。 相似文献
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7050铝合金是一种优秀的高强度铝合金,其各种半成品如板材、挤压材、锻件等在航空航天器制造中获得了广泛的应用,然而由于铸造性能差,其铸件未能得到应用。美国豪梅特研究公司(Howmet Research C0rp.)J.’r.斯特里(Staley)采用真空压铸法翩得了显微组织与性能良好的7050铝合金铸件,扩大了合金的应用范围。7050铝合金的真空压铸@王祝堂~~ 相似文献
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N. De Geyter R. Morent L. Gengembre S. Van Vlierberghe 《Surface & coatings technology》2008,202(13):3000-3010
In this paper, polyethylene terephthalate (PET) films are modified by a dielectric barrier discharge (DBD) in a helium/air mixture at medium (6.6 kPa) and atmospheric pressure. Surface analysis and characterization of the plasma-treated PET films is performed using contact angle measurements, X-ray Photoelectron Spectroscopy (XPS) and Atomic Force Microscopy (AFM). The polymer films, modified with the DBD at medium and atmospheric pressure, show a significant decrease in water contact angle due to the incorporation of oxygen-containing groups, such as C-O and O-C=O. Results also show that the surface treatment is uniform at micron scales, despite the fact that the discharge consists of a series of microdischarges. It is shown that at low energy densities (< ± 200 mJ/cm2), plasma treatment at medium pressure is more energy-efficient in incorporating oxygen functionalities than plasma treatment at atmospheric pressure. This effect could be induced by the larger diameter of the microdischarges at medium pressure than at atmospheric pressure (factor 3.92) and/or by the lower quenching of atomic oxygen in three-body collisions at medium pressure. The ageing behaviour of the plasma-treated PET films during storage in air is also studied in this paper. XPS results reveal that during the ageing process the induced oxygen-containing groups re-orientate into the bulk of the material. In this paper, it is shown that the ageing behaviour of the PET films is independent of the operating pressure used during plasma treatment. 相似文献
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Cold treatment of steel 总被引:1,自引:0,他引:1
A. P. Gulyaev 《Metal Science and Heat Treatment》1998,40(11):449-455
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1. | The laser-arc method of thermal hardening makes it possible to obtain hardened layers 2–3.5 thicker than in laser hardening with maintenance of a high microhardenss of 700–740 H (surface hardness 56–62 HRC). |
3. | Laser-arc treatment makes it possible to obtain hardened layers 4–6 mm wide and up to 1.0 mm deep with treatment rates up to 10 mm/sec and 3–4 mm wide and 0.4–0.6 mm deep with a rate of movement of the laser beam of 20–30 mm/sec. |
3. | An increase in arc length from 2 to 5 mm has practically no influence on the depth, width, and geometry of the laser action zone. |
5. | Defocusing of the laser beam (dL=2.0–4.0) with an increase in the rate of laser-arc treatment above 3.6 mm/sec is undesirable since in this case a high level of hardness is not obtained and localization of the beam is poorer. |
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