CAJ | 학술논문

为发展WC-Ni3Al-B复合材料的液相烧结制备技术,研究由羰基Ni粉、分析纯Al粉和粗WC粉的混合粉末反应合成制备的WC+Ni3Al预合金粉末.采用DSC和XRD分别研究3Ni+Al和70％WC+(3Ni+Al)混合粉末在550～ 1200 ℃和25～1400℃温度范围的相变过程.结果表明:Ni3Al相的形成取决于反应温度.在200～660 ℃热处理温度范围内,除了WC相外,还存在Ni2Al3、NiAl和Ni3Al相；而在660～1100 ℃温度范围内,仅存在NiAl和Ni3Al相;在1100～1200℃温度范围可以获得均匀的WC+Ni3A1预合金粉末混合物.采用该预合金粉末制备的WC-30％(Ni3Al-B)复合材料具有很高的致密度,且WC晶粒呈圆形.与普通商用YGR45(WC-30％(Co-Ni-Cr))相比,WC-30％(Ni3Al-B)复合材料具有更高的硬度(9.7 GPa),低的抗弯强度(1800MPa)和相近的断裂韧性(18MPa·m1/2).
위발전WC-Ni3Al-B복합재료적액상소결제비기술,연구유탄기Ni분、분석순Al분화조WC분적혼합분말반응합성제비적WC+Ni3Al예합금분말.채용DSC화XRD분별연구3Ni+Al화70％WC+(3Ni+Al)혼합분말재550～ 1200 ℃화25～1400℃온도범위적상변과정.결과표명:Ni3Al상적형성취결우반응온도.재200～660 ℃열처리온도범위내,제료WC상외,환존재Ni2Al3、NiAl화Ni3Al상；이재660～1100 ℃온도범위내,부존재NiAl화Ni3Al상;재1100～1200℃온도범위가이획득균균적WC+Ni3A1예합금분말혼합물.채용해예합금분말제비적WC-30％(Ni3Al-B)복합재료구유흔고적치밀도,차WC정립정원형.여보통상용YGR45(WC-30％(Co-Ni-Cr))상비,WC-30％(Ni3Al-B)복합재료구유경고적경도(9.7 GPa),저적항만강도(1800MPa)화상근적단렬인성(18MPa·m1/2).
In order to develop the liquid phase sintering process of WC-Ni3Al-B composites,the preparation process of WC+Ni3Al prealloyed powder by reaction synthesis of carbonyl Ni,analytical purity Al and coarse WC powders was investigated.DSC and XRD were adopted to study the procedure of phase transformation for the 3Ni+Al and 70％WC+(3Ni+Al) mixed powders in temperature ranges of 550-1200 ℃ and 25-1400 ℃,respectively.The results demonstrate that the formation mechanism of Ni3Al depends on the reaction temperature.Besides WC phase,there exist Ni2Al3,NiAl and Ni3Al intermetallics in the powder mixture after heat treatment at 200-660 ℃,while only NiAl and Ni3Al exist at 660-1100 ℃.Homogeneous WC+Ni3Al powder mixture can be obtained in the temperature range of 1100-1200 ℃.The WC-30％(Ni3Al-B) composites prepared from the mixed powders by conventional powder metallurgy technology show nearly full density and the shape of WC is round.WC-30％(Ni3Al-B) composites exhibit higher hardness of 9.7 GPa,inferior bending strength of 1800 MPa and similar fracture toughness of 18 MPa·m1/2 compared with commercial cemented carbides YGR45 (WC-30％(Co-Ni-Cr)).