High Melting Points of Tantalum in a Laser-Heated Diamond Anvil Cell
High Melting Points of Tantalum in a Laser-Heated Diamond Anvil Cell
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DOI：
10.1103/physrevlett.104.255701
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发表时间：
2010-06-21
影响因子：
8.6
通讯作者：
Loubeyre, Paul
中科院分区：
文献类型：
--
作者：
Dewaele, Agnes;Mezouar, Mohamed;Loubeyre, Paul
原位X射线衍射已被用来表征强激光照射下的钽样品的结构修改，高达135 GPa的金刚石压砧单元。获得的解链数据点不证实先前报道的异常低的解链曲线。确定了两种影响，可能会改变高静压下的难熔金属，如钽的熔化测定。首先，观察到Ta与压力传递介质以及与从砧表面扩散出的碳的强化学反应性。其次，当压力介质熔化时，高温测量可能会失真。从头计算，冲击测量和静态测定之间的强烈分歧在这里得到解决，因此排除了许多理论解释。最后，体心立方相是稳定的压力-温度范围内调查。
In situ x-ray diffraction has been used to characterize the structural modifications of tantalum samples under intense laser irradiation, up to 135 GPa in a diamond anvil cell. Melting data points are obtained that do not confirm the previously reported anomalously low melting curve. Two effects are identified that might alter the melting determination of refractory metals such as Ta under high static pressures. First, a strong chemical reactivity of Ta with the pressure transmitting media and with carbon diffusing out from the surface of the anvils is observed. Second, pyrometry measurements can be distorted when the pressure medium melts. The strong divergence between ab initio calculations, shock measurements and static determination is resolved here and hence many theoretical interpretations are ruled out. Finally, the body-centered cubic phase is stable over the pressure-temperature range investigated.