(福州大學 材料科學與工程學院，福州 350108)
摘 要: 在氨基磺酸鎳體系的鍍液中通過直流、脈沖電沉積分別制備了不同晶粒尺寸的塊體鎳。通過室溫單向拉伸實驗比較了這些鎳的力學性能。 結果表明：拓寬電沉積納米鎳的晶粒尺寸分布可顯著提高其塑性，同時，保留較高的強度。所制備的具有寬晶粒尺寸分布(5~120 nm)的平均晶粒尺寸為27.2 nm的納米鎳，抗拉強度為1 162~ 1 211 MPa，斷裂伸長率為10.4%~11.4%。與平均晶粒尺寸為22.4 nm的窄晶粒尺寸分布(5~60 nm)的納米鎳相比，抗拉強度降低約200 MPa，但斷裂伸長率提高了3.4%。通過對納米鎳微觀組織的TEM觀察，揭示了寬晶粒尺寸分布納米鎳中塑性的顯著提高源于塑性變形中大晶粒(100 nm以上)內(nèi)存在類似傳統(tǒng)粗晶材料中的晶內(nèi)位錯滑移。
附件:17-p1815-07-17895關鍵詞:納米鎳；力學性能；變形機制；電沉積
關鍵字: 納米鎳；力學性能；變形機制；電沉積
electrodeposited microcrystalline and nanocrystalline Ni
（College of Materials Science and Engineering, Fuzhou University, Fuzhou 350108, China）
Abstract:The bulk Ni with various grain sizes were prepared by direct current or pulse electrodeposition, respectively, in the nickel sulfamate electrolyte. The uniaxial tensile tests were performed at room temperature to compare the mechanical properties among these Ni samples. The results show that the ductility in electrodeposited nanocrystalline (NC) Ni can be significantly enhanced with a higher strength by extending the grain size distribution. The NC Ni samples with a broad grain size distribution (5−120 nm) and an average grain size of 27.2 nm have an ultimate tensile strength (σUTS) of 1 162−1211 MPa and an elongation to failure (δETF) of 10.4%−11.4%. Compared with the NC Ni samples that have a narrow grain size distribution (5−60 nm) and an average grain size of 22.4 nm, the σUTS of NC Ni with a broad grain size distribution decreases by 200 MPa, but the δETF increases by 3.4%. By the TEM observations of the microstructures in NC Ni, it is revealed that the apparent enhancement of ductility in NC Ni with a broad grain size distribution results from the presence of intragranular dislocation sliding in the large grains (above 100 nm) during plastic deformation, similar to that in conventional coarse-grained materials.
Key words: nanocrystalline Ni; mechanical property; deformation mechanism; electrodeposition
