Study of residue type defect formation mechanism and the effect of advanced defect reduction (ADR) rinse process

Author(s):  
Hiroshi Arima ◽  
Yuichi Yoshida ◽  
Kosuke Yoshihara ◽  
Tsuyoshi Shibata ◽  
Yuki Kushida ◽  
...  
Author(s):  
Kevin Jones ◽  
Emily Turner ◽  
Jae Young Lee ◽  
Hans van Meer ◽  
Naushad Variam ◽  
...  

2020 ◽  
Vol 321 ◽  
pp. 10001
Author(s):  
K. Kelkar ◽  
A Mitchell

Beta fleck is a troublesome segregation defect in many titanium alloys. It has previously been investigated by several authors and appears to have two formation mechanisms, one similar to that of “freckle” in steels and nickel-base alloys, the other arising in the “crystal rain” effect seen in conventional steel ingots. The freckle defect has been extensively studied and several theories developed to account for its formation in both remelted ingots and directional castings. In this work we compare the findings of investigations into the nickel-base freckle formation mechanism to similar conditions in the vacuum arc remelting of titanium alloys. We find that there are strong similarities between the beta fleck formation conditions and the parameters related to the Rayleigh Number criterion for freckle formation. In particular, the dendritic solidification parameters and the density dependence on segregation coefficients both fit well with the conditions proposed to characterise freckle formation. The second formation mechanism arises in the columnar to equiax transition in solidification. The condition for the avoidance of the defect in the two cases is the shown to be the same, namely the use of a very low VAR melting rate, but that it is unlikely to be 100% successful in preventing defect formation. We propose that the techniques presently in use for alloy development in the superalloy field through optimising the composition for minimum sensitivity to freckle formation should be applied to the formulation of future titanium alloys; also that attention should be paid to developing the PAM process to provide suitable solidification conditions for defect absence in a final ingot.


2017 ◽  
Vol 34 (1) ◽  
pp. 40-44 ◽  
Author(s):  
Hao Zhang ◽  
Yang Liu ◽  
Fenglian Sun ◽  
Gaofang Ban ◽  
Jiajie Fan

Purpose This paper aimed to investigate the effects of nano-copper particles on the melting behaviors, wettability and defect formation mechanism of the Sn58Bi composite solder pastes. Design/methodology/approach In this paper, the mechanical stirring method was used to get the nano-composite solder pastes. Findings Experimental results indicated that the addition of 3 wt.% (weight percentage) 50 nm copper particles showed limited effects on the melting behaviors of the Sn58Bi composite solder paste. The spreading rate of the Sn58Bi composite solder paste showed a decreasing trend with the increase of the weight percentage of 50 nm copper particles from 0 to 3 wt.%. With the addition of copper particles of diameters 50 nm, 500 nm or 6.5 μm into the Sn58Bi solder paste, the porosities of the three types of solder pastes showed a similar trend. The porosity increased with the increase of the weight percentage of copper particles. Based on the experimental results, a model of the void formation mechanism was proposed. During reflow, the copper particles reacted with Sn in the matrix and formed intermetallic compounds, which gathered around the voids produced by the volatilization of flux. The exclusion of the voids was suppressed and eventually led to the formation of defects. Originality/value This study provides an optimized material for the second and third level packaging. A model of the void formation mechanism was proposed.


2007 ◽  
Author(s):  
Lin-Hung Shiu ◽  
Fu-Jye Liang ◽  
Hsing Chang ◽  
Chun-Kuang Chen ◽  
Li-Jui Chen ◽  
...  

2008 ◽  
Vol 517 (1) ◽  
pp. 407-411 ◽  
Author(s):  
Norio Hirashita ◽  
Shu Nakaharai ◽  
Yoshihiko Moriyama ◽  
Koji Usuda ◽  
Tsutomu Tezuka ◽  
...  

1994 ◽  
Vol 75 (3) ◽  
pp. 1599-1606 ◽  
Author(s):  
P. Kounavis ◽  
D. Mataras ◽  
N. Spiliopoulos ◽  
E. Mytilineou ◽  
D. Rapakoulias

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