英语翻译Therefore,emphasis will be placed more on the location of the S-L interface as it conformswith the overall mass transfer.Namely,at steady state,the liquidus isotherm of the clad materialhas to completely span from the bottom to the top of
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英语翻译Therefore,emphasis will be placed more on the location of the S-L interface as it conformswith the overall mass transfer.Namely,at steady state,the liquidus isotherm of the clad materialhas to completely span from the bottom to the top of
英语翻译
Therefore,emphasis will be placed more on the location of the S-L interface as it conforms
with the overall mass transfer.Namely,at steady state,the liquidus isotherm of the clad material
has to completely span from the bottom to the top of the clad layer (this is depicted in figs.4-6,
which also illustrate the behavior of the temperature field during the process of mesh generation).
If in a computer run this condition is not achieved,this means that the available laser energy is not
enough to produce a clad layer of the previously assumed thickness.Therefore,in keeping the
same clad height (which,for a given speed,corresponds to a certain powder feed rate),the power
and/or scanning speed has to be adjusted accordingly.On the other hand,if this isotherm drops
considerably to the substrate,that would mean that the clad layer would become diluted,so
parameters should be adjusted.This iterative process should continue,until a limit condition is
satisfied.The limit condition imposed is that the lowest point of the clad material liquidus isotherm
is located at the clad-substrate interface,a procedure considered by Hoadley and Rappaz
6 .In that
case,the set of process parameters is taken as one that leads to a possible cladding operation (as
long as the liquidus isotherm still hits the top surface of the clad region).In this way,a parametric
study can be undertaken,in such a way that a region of successful cladding can be defined in the
{absorbed power,absorbed feed rate,scanning speed} parameter space,for a certain experimental
setup (i.e.optical and powder delivery systems) and clad-substrate materials.
2.2 Thermal stresses modeling
As the clad and substrate are heated,thermal strain will develop in the material.This field
will not be uniform because:a) the temperature is not uniform; b) clad and substrate have,in
general,different values for the thermal expansion coefficient.Stresses in the elastic domain will
be generated and,most likely,conditions for inelastic deformation will become present,as the flow
stress decreases markedly with temperature,while the elastic moduli are not expected to undergo
such a sharp drop.When the thermal load is removed,permanent deformation will result in
residual stresses,mostly concentrated at the clad-substrate interface.
英语翻译Therefore,emphasis will be placed more on the location of the S-L interface as it conformswith the overall mass transfer.Namely,at steady state,the liquidus isotherm of the clad materialhas to completely span from the bottom to the top of
所以,将更重视S-L接口的地点,因为它一致整体传递.即,在稳定时,包覆材料的liquidus等温线必须从底部完全地跨过在穿的层数的上面(这在figs.被描述4-6,也说明温度领域行为在滤网世代的过程中).如果在计算机跑这个情况没有达到,这意味着可利用的激光能不是导致的足够以前假设的厚度的穿的层数.所以,在保留,被测量的速度的,对应于某一粉末供给率)的同一穿的高度(力量和扫描速度必须相应地被调整.在另一只手上,如果这条等温线相当地下降到基体,意味穿的层数将变得稀释,如此 应该调整参量.这个重复过程应该继续,直到极限状态是满意的.强加的极限状态是包覆材料liquidus等温线的最低的点位于穿基体接口、Hoadley考虑的做法和Rappaz 6.由于 案件,套过程参数被采取,那导致可能的金属操作的一个(只要liquidus等温线仍然击中穿的区域的顶面).这样,一项参数研究可以为某一实验性设定(即光学和粉末送货系统)和穿基体材料被承担,在这种情况下成功的金属的区域可以被定义在{被吸收的力量,吸收了供给率,扫描速度}参数空间.2.2热应力塑造 因为穿和基体激昂,热量张力在材料将开发.这个领域不会是一致的,由于:a)温度不是一致的; b)穿和基体有,一般来说,热扩散系数的不同的价值.在有弹性领域的重音将引起,并且,很可能,无弹性的变形的条件将变得当前,流程重音明显减少与温度,而弹性模数没有预计接受这样暴跌.当去除热量装载,永久变形将发生 剩余应力,主要被集中在穿基体接口.