Bulk Ni-W alloys with a composite-like microstructure processed by spark plasma sintering: Microstructure and mechanical properties
Bulk Ni-W alloys with a composite-like microstructure processed by spark plasma sintering: Microstructure and mechanical properties
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DOI：
10.1016/j.matdes.2015.10.083
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发表时间：
2016-01-05
影响因子：
8.4
通讯作者：
Ameyama, K.
中科院分区：
文献类型：
--
作者：
Sadat, T.;Dirras, G.;Ameyama, K.
采用放电等离子烧结技术对Ni粉和W粉的混合粉末进行Ni-W合金的烧结。W的量在10至65重量%的范围内。XRD和EBSD研究表明，Ni（W）固溶体的形成沿着纯W和WC或Ni 6 W 6C碳化物相的群集，这取决于初始W量。通过拉伸和硬度测试研究了其力学性能，并与块体Ni对应物进行了比较。增加W的量导致Ni（W）组分的晶粒尺寸减小，这可能是由于W溶质原子的晶界钉扎。这也伴随着硬度和强度的增加，但以塑性应变为代价。SEM研究表明，复合材料的微观结构的W团簇的脆性断裂，而Ni（W）固溶体对应物表现出韧性行为。在加工的材料中，含有类似于30重量%的初始W量的合金表现出强度和均匀应变的最佳组合（分别类似于800 MPa和类似于30%），这可能与来自各种强化源的鸡尾酒样效应有关，例如Ni（W）的固溶体晶粒尺寸减小，其也显示出高数量的σ 3边界。(C)2015爱思唯尔有限公司版权所有。
Spark plasma sintering was used to process Ni-W alloys from blends of Ni and W powders. The W amount ranged from 10 to 65 wt.%. XRD and EBSD investigations revealed the formation of Ni(W) solid solution along with clusters of pure W and remote quantities of WC or Ni6W6C carbide phases, depending on the initial W amount. The mechanical properties were investigated by tensile and hardness tests and compared to bulk Ni counterpart. Increasing the amount of W resulted in a grain size decrease of the Ni(W) component, probably due to grain boundary pinning by W solute atoms. This was also accompanied by an increase of both hardness and strength but at the expense of plastic strain. SEM investigations of the composite-like microstructures showed brittle fracture of the W clusters, whereas the Ni(W) solid solution counterpart exhibited a ductile behavior. Amongst the processed materials, the alloy containing an initial W amount of similar to 30 wt.% exhibited the best combination of strength and uniform strain (similar to 800 MPa and similar to 30%, respectively), which can be related to a cocktail-like effect coming from various strengthening sources, such as solid solution grain size reduction of the Ni(W), which also displayed a high number of Sigma 3 boundaries. (C) 2015 Elsevier Ltd. All rights reserved.