By what means kind of small area or stripe be selectively hardened and a large steel pa

The strength in the weld zone of an age-hardening aluminium alloy is often higher than in the heat affect zone (HAZ). Which of the following is NOT a reason for this? O The maximum temperature is higher in the weld pushing more of the hardening phase into solution. O Particles that don't dissolve might transform into equilibrium phases instead. This is more likely in the HAZ. O The greater dissolution of particles in the weld leads to greater solid solution strengthening. O The increase in solute in the matrix allows more subsequent natural aging to occur in the weld zone. O Particles in the HAZ tend to dissolve, while those in the weld coarsen. The increase in particle size and spacing reduces the strength of HAZ.

Fatigue life of a material is higher if it has, A. High stiffness and low toughness B. Pores due to processing C. High Toughness and low hardness D. Fast crack propagation E. All of the above.

Which tool steel group would be the best for master gauges? D M P S