INDEX Alloying methods

The rotational temperature obtained from a linear relation in the Boltzmann plot of the rotational energy distribution is an index of the lifetime in the intermediate excited state and decreases with decreasing lifetime. The rotational temperature of CO desorbed from Pt(l 1 1) is very low as compared with that of NO desorption, i.e. the lifetime of the excited CO is supposed to be much shorter than that of NO. In the case of CO desorption from Pt(l 11), however, the lifetime is not obtained from the rotational energy distribution, since desorbed molecules are detected by the (2 + 1 )REMPI method in the experiment [ 12] and then the single rotational states are not resolved. On the other hand, the rotational temperature of NO desorbed from Pt(l 1 1)-Ge surface alloy is lower than that from Pt(l 1 1). Then, it is speculated that the lifetime of the excited CO on the alloy is shorter than that on Pt( 111) and the residence time of the excited CO on the alloy is too short to be desorbed. As a consequence, the excited CO molecules are recaptured in the relaxation without desorption. However, it has not been understood why the lifetime of the excited CO molecule (or the excited CO-Pt complex) on Pt( 1 1 1) is shorter than that of the excited NO molecule (complex) on Pt(l 11), and further on the Pt-Ge alloy as compared with Pt(l 1 1). 

One further group of surface alloy phases which have been studied by quantitative structural methods are those formed by Sn on all three low index faces of Ni as well as Cu(lll), Pt(lll), Pt(lOO) and Rh(lll). In part these investigations were motivated by the fact that Sn addition to some transition... 

By the method of mathematical multifactor planning of the experiment, equations were derived that describe the dependence of the mechanical properties of parent and weld metals on the chemical composition of the alloy. Table III shows the investigated factors, intervals, and levels of variation. Characteristics of mechanical properties and the index of alloy susceptibility to hot cracking of weld metal during welding served as functions of response. 

The second method of ASTM G 101 uses a predictive equation, based on the chemical composition of the steel, to calculate a corrosion resistance index. If the index for a specific steel composition falls within the range normally expected for weathering steel, the indication is that the steel in question contains sufficient alloying elements (in the proper proportion) such that it should perform as a weathering steel. Averages and ranges of corrosion resistance indices, taken from ASTM G 101, for ASTM A 242 and ASTM A 588 steels, ai shown in Table 3. 

Hardness is a cost-effective index that reflects a first-order approximation of the prior heat treatment. This method is particularly relevant because of the long list of engineering alloys that are precipitation hardenable, such as 2024 and 7075 aluminum alloys, 17-4 PH stainless steel, maraging steel. Inconel 718, Rene 41, and Waspaloy. In many reverse engineering projects, engineers are working on the parts made of these alloys. However, for a precise reverse engineering of heat treatment, more analyses and substantiation data are required. 

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